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The functional role of long non-coding RNAs and epigenetics

Jinneng Cao

Biological Procedures Online · 2014 · Review

doi:10.1186/1480-9222-16-11

Abstract

Long non-coding RNAs (lncRNAs) are non-protein coding transcripts longer than 200 nucleotides. The post-transcriptional regulation is influenced by these lncRNAs by interfering with the microRNA pathways, involving in diverse cellular processes. The regulation of gene expression by lncRNAs at the epigenetic level, transcriptional and post-transcriptional level have been well known and widely studied. Recent recognition that lncRNAs make effects in many biological and pathological processes such as stem cell pluripotency, neurogenesis, oncogenesis and etc. This review will focus on the functional roles of lncRNAs in epigenetics and related research progress will be summarized.

Full text

From PubMed Central, U.S. National Library of Medicine, as current on Oct 18, 2026. Paragraph numbers are ours, so an answer can point at one.

Introduction

Messenger RNA (mRNA) is the RNA that carries information from DNA to the ribosome for protein synthesis. And yet, many RNAs do not code for proteins in eukaryotes. There are RNAs that lack an apparent open reading frame (ORF) of 300 nt or longer. They do not encode a protein product thus classified as putative noncoding RNAs. Long non-coding RNAs (lncRNAs) are molecules longer than 2 kb in length with a coding potential of less than 100 amino acids, or non-protein coding transcripts with the length of longer than 200 nucleotides (nt). For this definition, it somewhat arbitrary could not distinguish lncRNAs from small regulatory RNAs. Now, there have been identified far greater amounts of lncRNAs than protein coding genes. A majority of annotated eukaryotic protein-coding ORFs were characterized with high level of phylogenetic diversity and the conservation. And the level of its conservation and the rate of synonymous to no synonymous substitutions were applied as additional criteria. It also applied for distinguishing the protein-coding transcripts containing bona fide functional ORFs from non-coding transcripts among novel RNAs. As we know, there is an underlying dogma of molecular biology that the purpose of RNA is to direct the assembly of proteins from amino acids. However, a few exceptions to this paradigm were explored (such as ribosomal RNA and transfer RNA), which were functional RNA macromolecules that did not code for protein.

It has been reported that about 20% of transcription progress across the human genome would be associated with protein-coding genes. The fact indicates that lncRNAs is at least four-times longer than coding RNA sequences. However, it may be large-scale complementary DNA (cDNA) sequencing projects to reveal the complexity of transcription, such as FANTOM (Functional Annotation of Mammalian cDNA).

RNA is an information encoding molecule with high flexibility and high-fidelity. It has also been characterized with easy activation, modification, transportation, and degrasion. Thus, RNA is considered as an integrative character of both the digital lexicon of DNA and the analog language of proteins. It is also a dynamic participant of DNA and protein molecules in performing cellular activities.

According to taxonomic, non-coding RNAs (ncRNAs) are composite of the familial "housekeeping" RNAs and regulatory RNAs in recent intensive studies. There are many different sizes of NcRNAs and for this reason they have been divided into small and long classes: small ncRNAs (sncRNA) being less than 200 nt and lncRNA greater than 200 nt to over 100 kb in length. The current cut-off has been arbitrary and corresponds to specific biochemical protocols. Most categories of small infrastructural or regulatory RNAs have been excluded (tRNAs, snRNAs, miRNAs, siRNAs, piRNAs, tiRNAs, spliRNAs, sdRNAs and others) (Figure 1).

It is predicted that there are thousands of lncRNAs in the mammalian transcriptome. No strict minimal size is required for classifying a noncoding transcript as a "long" non-coding RNA and there were many lncRNAs with thousands of nucleotides. There are no clear-cut, uniformly available criteria for determining a non-coding character of an RNA. The widely accepted method for distinguishing protein-coding and non-coding RNAs among novel transcripts has analyzed the ORFs in each transcript as a primary criterion.

Epigenetics associated with a gene activity state that may be stable over long periods of time, persist through many cell divisions, or even be inherited through several generations and all without any variations to the primary DNA sequence. What is the relationship of lncRNAs and epigenetics? In this review, the recent studies will be included and we have tried to demonstrate the function of lncRNAs and its influences on epigenetics.

The function of lncRNAs

LncRNAs were considered as non-functional junk initially. And now, their presence and significance have still being debated. It is now apparently observed that many lncRNAs are the key regulators of transcriptional and translational output and therefore make effects on cell identify and function (Figure 2). However, different from general mRNAs exported to the cytoplasm for translation, many lncRNAs are now known to be restrained in various sub-nuclear compartments, which suggesting that such RNAs may have a potential function in the compartment where they are located.

Studies have shown that lncRNAs play critical regulatory roles in diverse cellular processes such as chromatin remodeling, transcription, post-transcriptional processing and intracellular trafficking (Figure 3). LncRNAs could be a highly abundant, rapidly evolving class of cellular factors with a wide range of cellular functions.

Imprinting

Imprinting has been a significant process in identifying special nucleic acid and protein, such as DNA methylation and histone modification. LncRNAs have been found to participate in imprinting processes. It means lncRNAs influence the monoallelic expression of a gene according to its parents of origin. More than 200 lncRNAs were found to participate in imprinting processes. Depending on their parental origins, differentially methylated regions unmethylated DNA imprinting control regions (ICRs), resulting in specific expression of nearby lncRNAs and suppressing neighboring genes in cis.

The H19 lncRNA-MBD1 complex could interact with histone lysine methyltransferases. Therefore, it could work by bringing repressive histone marks on the differentially methylated regions of the three direct targets of the H19 gene.

Airn and Kcnq1ot1/LIT1 (Kcnq1 opposite transcript 1, or long QT intronic transcript 1) are examples of lncRNAs that cause suppression of paternally inherited genes. In particular, Kcnq1ot1/LIT1 is involved in the repression of several protein-coding genes in cis by interacting with repressive chromatin modifying complexes. Kcnq1ot1/LIT1 is an imprinted region contains at least eight genes that are expressed exclusively or preferentially from the maternal allele. Kcnq1ot1/LIT1 acts as an organizer on a tissue/lineage-specific nuclear domain, involving in epigenetic silencing of the Kcnq1 imprinting control region.

Developmental regulation

LncRNAs have played crucial roles in controlling gene expression during both developmental and differentiation processes. Furthermore, the number of lncRNA species will be higher in genomes of developmentally complex organisms. It highlights the significance of RNA-based levels of control in the evolution of multi-cellular organisms. Expression of lncRNAs is dynamically regulated during male germline development. On the contrary, lncRNAs may function to regulate gene expression at both transcriptional and posttranscriptional levels based on both genetic and epigenetic mechanisms.

MEG3 (Gtl2) was a lncRNAs in human with the length of about 1.6 kb. There are a number of splice isoforms in MEG3 and it retains introns creating longer transcripts. Recent studies have shown that Meg3 splicing isoform was silenced and in pituitary tumor, cancer cell growth would be inhibited by its ectopic expression. All these results suggested that Meg3 RNA acted as a growth suppressor. Furthermore, MEG3 expression is not only associated with tumor grade, but also suppressing DNA synthesis and stimulating p53-mediated trans-activation in meningiomas cell lines. Meg3 may play vital anti-tumor effects in tongue squamous cell carcinoma pathogenesis and represent potential prognostic biomarkers for stratification of patients with tongue squamous cell carcinoma.

Diseases associated induction/derivation

More and more evidences have proved that lncRNAs play critical roles in various biological processes. The mutations and dys-regulations of these lncRNAs contribute to the development of many complex diseases, such as virus infection and carcinogenesis. Beta2.7 is the popular one being studied in virus infection. Generally, beta2.7 specifically binds and prevents the re-localization of essential complex I subunit GRIM-19 (gene associated with retinoid/interferon-induced mortality-19). In response to apoptotic stimuli, beta2.7 is responsible for stabilizing the mitochondrial membrane potential and mitochondrial ATP production. It also prevents metabolic dys-function, which will be essential for completing the virus’ life cycle. The reactive oxygen species production will be reduced by the over-expression of beta2.7 RNA, thus the apoptosis could be inhibited. LncRNAs have been strongly associated with cancer. The expression of LncRNA PRINS (Psoriasis susceptibility-related RNA Gene Induced by Stress) will be in psoriatic epidermis and it will also be regulated by the proliferation and differentiation state of keratinocytes. In keratinocytes, the expression of G1P3 is an anti-apoptotic protein with high expression in psoriasis and it will be regulated by lncRNA PRINS.

LncRNAPCAT-1, a target gene of polycomb repressive complex 2, has been implicated in disease progression by promoting cell proliferation. The up-regulation of ANRIL (antisense non-coding RNA in the INK4 locus) is required for the expression of the tumor suppressors INK4a/p16 and INK4b/p15 in prostate cancer. HOTAIR up-regulation is associated with poor prognosis in breast cancer, liver, colorectal, gastrointestinal and pancreatic cancers. Meanwhile, it also probably contributes to promote the tumor invasiveness and metastasis. In human melanomas, approximately 50 genes have been partly regulated by hyper-methylation of CpG islands in their regulatory regions.

Compared with DNA or protein, RNA molecules are considered to be more efficiently couple bioenergetic requirements with information storage and processing. Therefore, the advent of RNA based networks is thought to be responsible for fueling the explosive evolutionary innovations, which may characterize the human brain form and function. The brain is a conspicuous consumer of energy resources. It is also a major consequence of cerebral ischemia for energy metabolism and exhaustion of adenosine triphosphate. Brain development and function are tightly regulated by epigenetic mechanisms by gene expression modulation in response to intrinsic and extrinsic signals. The lncRNAs are also dynamically expressed during pluripotency and differentiation in neural or glial cells. The knock-down of four lncRNAs has been associated with neuronal differentiation. The function of these mentioned IncRNAs were mainly physically interacted with SOX2, PRC2 complex component, REST and SUZ12. The cellular differentiation fate will be altered from a neurogenic to a gliogenic program. The results suggested the functional role of the lncRNAs in neural cell fate specification.

The versatile function of lncRNAs

There are many different functions of lncRNA has been explored in latest few years. Besides of transcription regulation, there are also several versatile lncRNAs that have been evidenced, such as Kcnq1ot1, Airn, Xist and HOTAIR. Their function have mainly focused on regulating transcription of multiple target genes through epigenetic modifications. For the insulin like growth factor 2 receptor (Igf2r) imprinted cluster, located on mouse chromosome 17, the expression of paternal-specific non-coding transcript antisense Igf2r RNA (Airn, 108 kb), is required for the silencing of three genes on the paternal allele. These genes have spread over a large genomic region spanning 400 kb. On the mouse X-chromosome, expression of X-inactive specific transcript (Xist) of lncRNA from the designated inactive X-chromosome is essential for the silencing of inactive X-chromosome. Some genes on the Homeobox D (HOXD) cluster are located over a 40 kb genomic region on human chromosome 2. These genes will be silenced by lncRNA HOTAIR, which is originated from the HOXC cluster on chromosome 12. On mouse chromosome 7, the potassium voltage-gated channel subfamily Q member 1 (Kcnq1) imprinted cluster spreads over a 1 Mb genomic region in embryos. Multiple genes are contained and it will be silenced on the paternal allele by the un-spliced lncRNA Kcnq1 overlapping transcript 1 (Kcnq1ot1, 91 kb) in cis. While, some lncRNAs, transcribed by RNA polymerase II, are able to recruit transcriptional repressive complexes including PcGs and G9a to silence specific genomic regions, both in cis (top) and in trans (bottom) (Figure 4).

Spliced lncRNAs, compared with such un-spliced as single exon transcripts, intergenic and cis-antisense RNAs are more stable than those derived from introns. The sub-cellular localization analysis indicates the location of lncRNAs is widespread in cell, with nuclear-localized lncRNAs more likely to be unstable.

LncRNAs and epigenetics

Epigenetics is applied to describe the study of heritable variations in gene activity which is independent of DNA sequence variations in genetics. It is generally applied to refer to epigenetic modifications on the genetic material of one cell. Epigenetics is analogous to genomics and proteomics and it is the study focusing on genome and proteome of one cell. Epigenetic modifications are reversible modifications on the DNA of one cell or histones that may affect gene expression without altering the DNA sequence.

LncRNAs linked with epigenetics by DNA methylation

Chromatin is the combination of DNA and proteins that collectively make up the contents of cell nucleus. Chromatin is in charge of DNA packaging, gene expression and DNA replication. The mechanism of epigenomic control is generally considered at the level of chromatin. Histones proteins can be chemically modified by as the process such as acetylation, methylation, sumoylation and ubiquitylation. The processes will result in structural variations in chromatin and the access of DNA will be allowed.

Recent findings reveal that lncRNAs are implicated in serial steps of cancer development. These lncRNAs interact with DNA, RNA, protein molecules and/or their combinations. It acts as an essential regulator in chromatin organization, transcriptional and post-transcriptional regulation. Their mis-expression confers the cancer cell capacities for tumor initiation, growth, and metastasis. There is also a review demonstrating the roles of lncRNAs in cancer diagnosis and therapy. It reported expression profiles were different for numerous lncRNA in urothelial cancer. The phenotype-specific expression and a potential mechanistic target were studied and it demonstrated that the IncRNAs may be prognostic biomarkers for this cancer. The LncRNAs such as up-regulation of HOTAIR could be associated with poor prognosis in breast cancer, liver, colorectal, gastrointestinal and pancreatic cancers. Meanwhile, it also probably contributes to promote the tumor invasiveness and metastasis.

There are CpG islands in the upstream region of the miR-375 gene and aberrant DNA methylation in this gene can be observed in specific melanoma stage. Histone modification of DNA methylation is one vital epigenetic mechanism to regulate the expression of genes. DNA methylation and histone modifications are epigenetic mechanisms leading to the deregulation of lncRNAs expression in cancers. Epigenetic up-regulation of lncRNAs at 13q14.3 in leukemia is linked to the down regulation of Cis. It is a gene cluster that targets in NF-kB. Normal melanocytes, keratinocytes and cell lines derived from stage one melanoma were minimal methylated at this locus. Whereas, the islands from cancer cells derived from stage three or more advanced metastatic melanoma samples were hyper-methylated. The tumor suppressor lncRNAs will be down-regulated or silenced by DNA methylation. And hence consequent up-regulation of oncogens would be involved in carcinogenesis. Hyper-methylated lncRNAs were re-expressed by demethylation treatment with DNA methylation transferase (DNMT) inhibitor, 5-azadC, within 24-96 h. The expression of hyper-methylated lncRNAs would be further enhanced by treatment in combination with histone deacetylase (HDAC) inhibitor such as 4-phenylbutyric acid or trichostatin. The fact indicated a collaborative role between DNA methylation and histone modifications during the silencing effect of tumor suppressive lncRNAs. A few DNA methyltransferase proteins including Dnmt3a and Dnmt3b, as well as methyl-DNA-binding domain proteins (MBDs), are able to form DNA-protein complexes.

As for human melanomas, abnormal methylation of the tumor suppressor RASSF1 is a hallmark of many cancers including uveal and metastatic melanoma. DNA methylation was considered as predictors of recurrence in non muscle invasive bladder cancer: an MS-MLPA approach.

Considering the complex origin of melanoma and the existence of heterogeneous subtypes, it is considered that the presence of a single biomarker would not be sufficient to make an informed diagnostic decision. The high affinity RNA-binding activity of MBD proteins was recently characterized and it seemed to be different from the methyl CpG DNA binding domain protein. It was hypothesized that DNMTs and MBD proteins may allow RNA molecules to participate in DNA methylation-mediated chromatin regulation.

Chromatin modifications appear to be correlated with CpG island methylation, in which methylation is repeatedly exhibited in tracts of DNA sequence at the fifth carbon atom of cytosines. Cytosine methylation is the only known endogenous modification of DNA in mammals and it occurs through DNA methyltransferase-mediated methylation.

There is one of the best understood mechanisms behind epigenetics. It involved methylation of cytosine residues at specific positions in the DNA molecule. It has well characterized the enzymes that have carried out the methylation reaction. The mechanism is that the configuration of methylated positions is propagated through DNA replication. The typical consequence of methylation in a genomic region is the repression of nearby genes.

Epigenetic role for lncRNAs in gene regulation

A novel mechanism of epigenetic repression of the RASSF1A tumor suppressor gene has involved antisense unspliced lncRNA. In this mechanism, the expression of the RASSF1 isoform has been selectively repressed by ANRASSF1, overlapping the antisense transcript in a location-specific manner.

During the latent infection of human cytomegalovirus (HCMV) in CD14 (+) and CD34 (+) cells, RNA4.9 interacts with components of the polycomb repression complex (PRC) as well as the MIE promoter region where the enrichment of the repressive H3K27me3 mark. It will also disclose the repression function of lncRNA on transcription.

Berghoff EG and his colleague have shown that Evf2 (Dlx6as) lncRNA antisense transcription, Evf2-dependent balanced recruitment of activator and repressor proteins enabled differentially transcriptional control of adjacent genes with shared DNA regulatory elements. Researches from another lab indicated that the intronic long non-coding RNA ANRASSF1 recruited PRC2 to the RASSF1A promoter, reducing the expression of RASSF1A and increasing cell proliferation. LncRNA loc285194 is a p53 transcription target; tumor cell growth is inhibited by ectopic expression of loc285194 both in vitro and in vivo.

The lncRNA-LET has been reduced by hypoxia-induced histone deacetylase 3 by reducing the associated histone acetylation-mediated modulation of the lncRNA-LET promoter region. And the down-regulation of lncRNA-LET was found to be a key step in the stabilization of nuclear factor 90 protein. It leads to hypoxia-induced cancer cell invasion. lncRNA-HEIH plays a key role in cell cycle arrest at stage G(0)/G(1). In addition, it was associated with enhancer of zeste homolog 2 (EZH2) and also required for the repression of EZH2 target genes.

TNFα expression is regulated by the long non-coding RNA THRIL (TNFα and hnRNPL related immunoregulatory LincRNA: large intergenic non-coding RNAs) through its interaction with hnRNPL (heterogeneous nuclear ribonucleoprotein L). Both activation and repression of immune response genes would be mediated by lincRNA-Cox2.

Epigenetic role for lncRNAs in gene activation

The dynamics of miRNA regulatory network mediated by RNA editing is implicated in stroke. LncRNAs-151 is found to be unregulated after middle cerebral artery occlusion. The immature form of lncRNAs-151 is subject to RNA editing that influences the primary lncRNAs processing into mature lncRNAs within the CNS. Intriguingly, lncRNAs-151 is thought to target in various cell cycle regulators as well as protein tyrosine kinase 2 (focal adhesion kinase), which is a non-receptor tyrosine kinase involved in integrin and growth factor signaling pathways. The pathways aredifferentially regulated after middle cerebral artery occlusion and implicated in modulating neurite outgrowth, neuronal plasticity, and restoration of neural network integrity within the ischemic penumbra. Furthermore, lncRNADQ786243 makes effects on regulating the expression of CREB and Foxp3, consequently with the regulation of T regulator cells in Crohn’s disease.

Enhancer-like activity of lncRNAs

Enhancer-associated (elncRNA) and promoter-associated (plncRNA) elements play different roles in the chromatin status at intergenic lncRNAs transcription. Expression of elncRNAs, but not plncRNAs, is associated with enhanced expression of neighboring protein-coding genes during erythropoiesis.

LncRNAs are dynamically expressed during erythropoiesis with epigenetic regulation. And they are targeted by key erythroid transcription factors such as GATA1, TAL1 and KLF1. After exploring 12 candidate lncRNAs, they were nuclear-localized, exhibiting complex developmental expression patterns. Depleting them severely impaired erythrocyte maturation, inhibiting cell size reduction and subsequent enucleation. lncRNA-EC7 is transcribed from an enhancer and is specifically needed for activation of the neighboring gene encoding BAND 3.

Recently, researchers have identified a translational regulatory lncRNA (trlncRNA) through genome-wide computational analysis. Furthermore, they found trlncRNA was upregulated in paired clinical breast cancer primary and lymph-node metastasis samples. Tumor invasion and metastasis will be stimulated by its expression in vitro and in vivo, respectively. In addition to this, trlncRNA is involved in the down-regulation of the epithelial marker E-cadherin by suppressing the translation of its mRNA.

The epigenetic influence on chromatin from lncRNAs

Cellular reprogramming is known to accompany cell type-specific epigenetic alterations of the genome. It is the conversion of one specific cell type to another. Chromatin structure and dynamics can be influenced by epigenetic factors such as covalent histone modifications, histone variants, DNA methylation, ncRNAs and etc. Chromatin remodeling complex may play an important role in cell fate decision. It has found that 28 lncRNAs are associated in cell invasiveness. It also represented the first key step for successful metastasis. Moreover, another ncRNA (HOTAIR long ncRNA) is able to promote cancer metastasis by inducing epigenetic variations in the chromatin state of cancer cells. Many tumor suppressor genes were found to carry antisense transcripts. For example, p15, a cyclin-dependent kinase inhibitor implicated in leukemia, possesses an antisense transcript and silencing its transcription in cis and in trans by inducing heterochromatin formation without changing DNA methylation in a Dicer-independent manner. It is possible that these antisense transcripts directly bind and recruit chromatin-modifying complexes to their associated sense transcripts. The role of non-coding RNAs in chromatin formation has also been observed in plants. One study found that targeted 3 prime processing of a non-coding antisense transcript to the FLC gene (a major floral repressor gene), resulting in the recruitment of FLD. It is a homolog of the human histone demethylase LSD1, which targets H3K4me2 for demethyaltion. Antisense mediated chromatin modifications appear to mostly operate in cis in contrast to lincRNAs which can operate both in cis and in trans.

The human body is composed of hundreds of distinct cell types. There is a specific position for each cell within the body and each cell performs a specific function. Since all the cells within a multi-cellular organism contain the same genome, the information that inducing cells to establish their identity is likely to be coded in their epigenome. The epigenome is comprised of modifications of DNA (i.e., DNA methylation) and modifications of histone proteins at specific amino acid residues (e.g., acetylation, methylation, phosphorylation, etc.). Key regulators of the epigenome are chromatin-modifying complexes that can add or remove covalent modifications to chromatin. The transcription factors can recognize and bind to specific DNA sequences. In contrast to transcription factors, the majority of chromatin-modifying complexes do not able to binding DNA. A major gap in our understanding of epigenetic regulation for chromatin-modifying complexes is how these complexes are targeted to specific regions of the genome. Recent studies have recently shown that the Jumanji protein Jarid2 could recruit the polycomb repressive complex (PRC)2 to its target sites in mouse embryonic stem cells. However, it showed a low expression in differentiated cells. Therefore, it is not clear how PRC2 is targeted to its genomic sites in other cell types. Also, there is a plethora of chromatin-modifying complexes without DNA binding protein partners to guide them to their action sites.

Similarly, several large lncRNAs transcribed antisense of protein-coding genes and they can also interact with chromatin modifying complexes and affect the landscape of chromatin. For example, the antisense transcript to the Igf2r gene is known as Air and it is required for the allele-specific silencing of several genes in the mouse placenta. The gene functions through direct interaction with the repressive histone methyltransferase G9a. Similarly, there is a nuclear retained antisense transcript in Kcnq1 gene (Kcnq1ot1). It associates in a tissue-specific manner with the Chromatin complexes G9a and PRC2 and several protein-coding genes within a 1 Mb region in cis will be repressed (Figure 5).

LncRNAs with epigenetic regulation

The mRNA of BCL2 will be negatively regulated by the miR-15a/16-1 group. As an anti-apoptotic gene in cancer, the frequent down-regulation of BCL2 suggests that the failure to induce apoptosis may be reason of melanoma development.

LncRNAs play critical roles in epigenetic modulation of chromatin structure by regulating key genes in specific cancerous cells. Distinct chromatin signatures are associated with lncRNAs encoding genes, and these signatures are demonstrably different in cancer cells, such as in colorectal carcinoma. It found that the expression of elncRNA, instead of plncRNA, was associated with enhanced expression of neighboring protein-coding genes during erythropoiesis. The regulation of lncRNA gene maternally encoded gene 3 by miR-29 and modulating the corresponding chromatin structures in hepatocellular carcinoma cells. DNMT-3A and DNMT-3B are direct targets of miR-29. It makes effects indirectly through the latter’s influences on DNMT gene expression. What is more, over-expressed lncRNAs can be potentially served as a required component of castration-resistance in prostatic tumors with Chromatin remodeling proteins such as Bmi1, Ring2 and Ezh2.

The significance of epigenetic regulation of lncRNAs in human melanoma cells is increasing with more evidence. LncRNAs was widely studied in such cancers as melanoma, colorectal, head and neck cancer. And LncRNAs clusters were differentially expressed in ovarian cancer cells with varying metastatic potentials. 4,956 lncRNAs have been detected in the microarray, 583 and 578 lncRNAs were upregulated and down-regulated, respectively. Seven of the analyzed lncRNAs (MALAT1, H19, UCA1, CCAT1, LOC645249, LOC100128881, and LOC100292680) confirmed the deregulation found by microarray analysis. LncRNAs play a partial or key role in epithelial ovarian cancer metastasis.

Conclusions and future directions

lncRNAs function make effects in many biological and pathological processes such as stem cell pluripotency, neurogenesis, oncogenesis and etc. In this review, it has focused on the functional roles of lncRNAs in epigenetics and summarized related research progress.

Reasoning, primary ncRNA precursor chains have a high frequency of nonsense codons in their short and highly interrupted ‘reading frames’. In addition, they will never be translated into proteins because they are too short. However, they may be associated with proteins that detect nonsense codons within a reading frame.

Thus, distinct forms of chromatin proteins may make effects through protein–protein contacts via the nonsense-mediated decay complex proteins. It might be able to organize in genes encoding ncRNA or lncRNAs. Chromatin will also be associated with a variety of other RNA binding proteins. In principle, ncRNAs could exert regulatory effects on the chromatin through their association with any of these proteins. Thus, much more exploratory work is needed in these fields.It was indicated that several ncRNAs are functional and not just ‘transcriptional noise’ as has been previously speculated. To the early geneticists, a ‘gene’ was a very abstract entity. It was only considered to reflect the way phenotypes were observed when transmitted between generations. Today, however, it is dispensable to re-evaluate the way for classifying ‘gene’ and genomic regions of apparently ‘gene poor’. It may produce important transcripts. All these will need to be tested with various methods for proving its clinical linkage to diseases.

Abbreviations

Anril: Antisense non-coding RNA in the ink4 locus; DNMT: DNA methylation transferase; ElncRNA: Enhancer-associated Long non-coding RNA; FANTOM: Functional Annotation of Mammalian cDNA; GRIM–19: Genes associated with retinoid/interferon-induced mortality-19; ICRs: Imprinting control regions; Kcnq1: Potassium voltage-gated channel subfamily Q member 1; LIT1: Long QT intronic transcript 1; LncRNA: Long non-coding RNA; MBD: Methyl-DNA-binding domain proteins; MBD1: Methyl-DNA-binding domain proteins; MEG3: Maternally expressed 3; mRNA: Messenger RNA; ncRNA: Non-coding RNA; ORF: Open reading frame; PlncRNA: Promoter-associated Long non-coding RNA; PRC: Polycomb repressive complex; PRINS: Psoriasis susceptibility-related RNA Gene Induced by Stress; sncRNA: Small non-coding RNAs; SncRNA: Small non-coding RNAs.

Competing interests

The author’s declare that he has no competing interests.

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    Chen LL Carmichael GG Decoding the function of nuclear long non-coding RNAsCurr Opin Cell Biol2010 22357364

    Not in our library10.1016/j.ceb.2010.03.003

  32. 32.

    Dinger ME Amaral PP Mercer TR Pang KC Bruce SJ Gardiner BB Askarian-Amiri ME Ru K Soldà G Simons C Sunkin SM Crowe ML Grimmond SM Perkins AC Mattick JS Long noncoding RNAs in mouse embryonic stem cell pluripotency and differentiationGenome Res2008 1814331445

    Not in our library10.1101/gr.078378.108

  33. 33.

    Loewer S Cabili MN Guttman M Loh YH Thomas K Park IH Garber M Curran M Onder T Agarwal S Manos PD Datta S Lander ES Schlaeger TM Daley GQ Rinn JL Large intergenic non-coding RNA-RoR modulates reprogramming of human induced pluripotent stem cellsNat Genet2010 4211131117

    Not in our library10.1038/ng.710

  34. 34.

    Fejes-Toth K Sotirova V Sachidanandam R Assaf G Hannon GJ Kapranov P Foissac S Willingham AT Duttagupta R Dumais E Gingeras TR Post-transcriptional processing generates a diversity of 5′-modified long and short RNAsNature2009 45710281032

    Not in our library10.1038/nature07759

  35. 35.
  36. 36.

    Hannon GJ Rivas FV Murchison EP Steitz JA The expanding universe of noncoding RNAsCold Spring Harb Symp Quant Biol2006 71551564

    Not in our library10.1101/sqb.2006.71.064

  37. 37.

    Hung T Chang HY Long noncoding RNA in genome regulation: prospects and mechanismsRNA Biol2010 7582585

    Not in our library10.4161/rna.7.5.13216

  38. 38.

    Pauli A Rinn JL Schier AF Non-coding RNAs as regulators of embryogenesisNat Rev Genet2011 12136149

    Not in our library10.1038/nrg2904

  39. 39.

    Valadkhan S Nilsen TW Reprogramming of the non-coding transcriptome during brain developmentJ Biol2010 95

    Not in our library10.1186/jbiol197

  40. 40.

    Mercer TR Dinger ME Mattick JS Long non-coding RNAs: insights into functionsNat Rev Genet2009 10155159

    Not in our library10.1038/nrg2521

  41. 41.

    Mercer TR Dinger ME Mariani J Kosik KS Mehler MF Mattick JS Noncoding RNAs in Long-Term Memory FormationNeuroscientist2008 14434445

    Not in our library10.1177/1073858408319187

  42. 42.

    He Y Meng XM Huang C Wu BM Zhang L Lv XW Li J Long noncoding RNAs: Novel insights into hepatocelluar carcinomaCancer Lett2014 3442027

    Not in our library10.1016/j.canlet.2013.10.021

  43. 43.

    Monnier P Martinet C Pontis J Stancheva I Ait-Si-Ali S Dandolo L H19 lncRNA controls gene expression of the Imprinted Gene Network by recruiting MBD1Proc Natl Acad Sci U S A2013 1102069320698

    Not in our library10.1073/pnas.1310201110

  44. 44.

    Pandey RR Mondal T Mohammad F Enroth S Redrup L Komorowski J Nagano T Mancini-Dinardo D Kanduri C Kcnq1ot1 antisense noncoding RNA mediates lineage-specific transcriptional silencing through chromatin-level regulationMol Cell2008 32232246

    Not in our library10.1016/j.molcel.2008.08.022

  45. 45.

    Kanduri C Thakur N Pandey RR The length of the transcript encoded from the Kcnq1ot1 antisense promoter determines the degree of silencingEMBO J2006 2520962106

    Not in our library10.1038/sj.emboj.7601090

  46. 46.

    Kanduri C Kcnq1ot1: a chromatin regulatory RNASemin Cell Dev Biol2011 22343350

    Not in our library10.1016/j.semcdb.2011.02.020

  47. 47.

    Clark MB Johnston RL Inostroza-Ponta M Fox AH Fortini E Moscato P Dinger ME Mattick JS Genome-wide analysis of long noncoding RNA stabilityGenome Res2012 22885898

    Not in our library10.1101/gr.131037.111

  48. 48.

    Jones MJ Bogutz AB Lefebvre L An extended domain of Kcnq1ot1 silencing revealed by an imprinted fluorescent reporterMol Cell Biol2011 3128272837

    Not in our library10.1128/mcb.01435-10

  49. 49.

    Mohammad F Mondal T Guseva N Pandey GK Kanduri C Kcnq1ot1 noncoding RNA mediates transcriptional gene silencing by interacting with Dnmt1Development2010 13724932499

    Not in our library10.1242/dev.048181

  50. 50.

    Fatica A Bozzoni I Long non-coding RNAs: new players in cell differentiation and developmentNat Rev Genet2014 15721

    Not in our library10.1038/nrg3606

  51. 51.

    Bao J Wu J Schuster AS Hennig GW Yan W Expression profiling reveals developmentally regulated lncRNA repertoire in the mouse male germlineBiol Reprod2013 89107

    Not in our library10.1095/biolreprod.113.113308

  52. 52.

    Zhang X Rice K Wang Y Chen W Zhong Y Nakayama Y Zhou Y Klibanski A Maternally expressed gene 3 (MEG3) noncoding ribonucleic acid: isoform structure, expression, and functionsEndocrinology2010 151939947

    Not in our library10.1210/en.2009-0657

  53. 53.

    Miyoshi N Wagatsuma H Wakana S Shiroishi T Nomura M Aisaka K Kohda T Surani MA Kaneko-Ishino T Ishino F Identification of an imprinted gene, Meg3/Gtl2 and its human homologue MEG3, first mapped on mouse distal chromosome 12 and human chromosome 14qGenes Cells2000 5211220

    Not in our library10.1046/j.1365-2443.2000.00320.x

  54. 54.

    Zhang X Zhou Y Mehta KR Danila DC Scolavino S Johnson SR Klibanski A A pituitary-derived MEG3 isoform functions as a growth suppressor in tumor cellsJ Clin Endocrinol Metab2003 8851195126

    Not in our library10.1210/jc.2003-030222

  55. 55.

    Zhang X Gejman R Mahta A Zhong Y Rice KA Zhou Y Cheunsuchon P Louis DN Klibanski A Maternally expressed gene 3, an imprinted noncoding RNA gene, is associated with meningioma pathogenesis and progressionCancer Res2010 7023502358

    Not in our library10.1158/0008-5472.can-09-3885

  56. 56.

    Jia LF Wei SB Gan YH Guo Y Gong K Mitchelson K Cheng J Yu GY Expression, Regulation and Roles of MiR-26a and MEG3 in Tongue Squamous Cell CarcinomaInt J Cancer2014 13522822293

    Not in our library10.1002/ijc.28667

  57. 57.

    Reeves MB Davies AA McSharry BP Wilkinson GW Sinclair JH Complex I binding by a virally encoded RNA regulates mitochondria-induced cell deathScience2007 31613451348

    Not in our library10.1126/science.1142984

  58. 58.

    Moon YM Lee J Lee SY Her YM Ryu JG Kim EK Son HJ Kwok SK Ju JH Yang CW Park SH Kim HY Cho ML Gene-associated retinoid-interferon-induced mortality 19 (GRIM-19) attenuates autoimmune arthritis by regulation of Th17 and Treg cellsArthritis Rheum2014 66569578

    Not in our library10.1002/art.38267

  59. 59.

    Zhao J Sinclair J Houghton J Bolton E Bradley A Lever A Cytomegalovirus beta2.7 RNA transcript protects endothelial cells against apoptosis during ischemia/reperfusion injuryJ Heart Lung Transplant2010 29342345

    Not in our library10.1016/j.healun.2009.09.006

  60. 60.

    Yu HC Bai L Yue SQ Wang DS Wang L Han H Dou KF Notch signal protects non-parenchymal cells from ischemia/reperfusion injury in vitro by repressing ROSAnn Hepatol2013 12815821

    Not in our library

  61. 61.

    Gutschner T Diederichs S The hallmarks of cancer: a long non-coding RNA point of viewRNA Biol2012 9703719

    Not in our library10.4161/rna.20481

  62. 62.

    Sonkoly E Bata-Csorgo Z Pivarcsi A Polyanka H Kenderessy-Szabo A Molnar G Szentpali K Bari L Megyeri K Mandi Y Dobozy A Kemeny L Szell M Identification and characterization of a novel, psoriasis susceptibility-related noncoding RNA genePRINS J Biol Chem2005 2802415924167

    Not in our library10.1074/jbc.m501704200

  63. 63.

    Szegedi K Sonkoly E Nagy N Németh IB Bata-Csörgo Z Kemény L Dobozy A Széll M The anti-apoptotic protein G1P3 is overexpressed in psoriasis and regulated by the non-coding RNAPRINS Exp Dermatol2010 19269278

    Not in our library10.1111/j.1600-0625.2010.01066.x

  64. 64.

    Bayley JP van Minderhout I Hogendoorn PC Cornelisse CJ van der Wal A Prins FA Teppema L Dahan A Devilee P Taschner PE Sdhd and SDHD/H19 knockout mice do not develop paraganglioma or pheochromocytomaPLoS One2009 4e7987

    Not in our library10.1371/journal.pone.0007987

  65. 65.

    Swindell WR1 Johnston A Xing X Voorhees JJ Elder JT Gudjonsson JE Modulation of epidermal transcription circuits in psoriasis: new links between inflammation and hyperproliferationPLoS One2013 8e79253

    Not in our library10.1371/journal.pone.0079253

  66. 66.

    Prensner JR Iyer MK Balbin OA Dhanasekaran SM Cao Q Brenner JC Laxman B Asangani IA Grasso CS Kominsky HD Cao X Jing X Wang X Siddiqui J Wei JT Robinson D Iyer HK Palanisamy N Maher CA Chinnaiyan AM Transcriptome sequencing across a prostate cancer cohort identifies PCAT-1, an unannotated lincRNA implicated in disease progressionNat Biotechnol2011 29742749

    Not in our library10.1038/nbt.1914

  67. 67.
  68. 68.

    Kotake Y Nakagawa T Kitagawa K Suzuki S Liu N Kitagawa M Xiong Y Long non-coding RNA ANRIL is required for the PRC2 recruitment to and silencing of p15 (INK4B) tumor suppressor geneOncogene2011 3019561962

    Not in our library10.1038/onc.2010.568

  69. 69.

    Popov N Gil J Epigenetic regulation of the INK4b-ARF-INK4a locus: in sickness and in healthEpigenetics2010 5685690

    Not in our library10.4161/epi.5.8.12996

  70. 70.
  71. 71.

    Gupta RA Shah N Wang KC Kim J Horlings HM Wong DJ Tsai MC Hung T Argani P Rinn JL Wang Y Brzoska P Kong B Li R West RB van de Vijver MJ Sukumar S Chang HY Long non-coding RNA HOTAIR reprograms chromatin state to promote cancer metastasisNature2010 46410711076

    Not in our library10.1038/nature08975

  72. 72.

    Yang Z Zhou L Wu LM Lai MC Xie HY Zhang F Zheng SS Overexpression of long non-coding RNA HOTAIR predicts tumor recurrence in hepatocellular carcinoma patients following liver transplantationAnn Surg Oncol2011 1812431250

    Not in our library10.1245/s10434-011-1581-y

  73. 73.

    Kogo R Shimamura T Mimori K Kawahara K Imoto S Sudo T Tanaka F Shibata K Suzuki A Komune S Miyano S Mori M Long noncoding RNA HOTAIR regulates polycomb-dependent chromatin modification and is associated with poor prognosis in colorectal cancersCancer Res2011 7163206326

    Not in our library10.1158/0008-5472.can-11-1021

  74. 74.

    Niinuma T Suzuki H Nojima M Nosho K Yamamoto H Takamaru H Yamamoto E Maruyama R Nobuoka T Miyazaki Y Nishida T Bamba T Kanda T Ajioka Y Taguchi T Okahara S Takahashi H Nishida Y Hosokawa M Hasegawa T Tokino T Hirata K Imai K Toyota M Shinomura Y Upregulation of miR-196a and HOTAIR drive malignant character in gastrointestinal stromal tumorsCancer Res2012 7211261136

    Not in our library10.1158/0008-5472.can-11-1803

  75. 75.

    Kim K Jutooru I Chadalapaka G Johnson G Frank J Burghardt R Kim S Safe S HOTAIR is a negative prognostic factor and exhibits pro-oncogenic activity in pancreatic cancerOncogene2013 3216161625

    Not in our library10.1038/onc.2012.193

  76. 76.

    Rothhammer T Bosserhoff AK Epigenetic events in malignant melanomaPigment Cell Res2007 2092111

    Not in our library10.1111/j.1600-0749.2007.00367.x

  77. 77.

    Xia J Zhang X Yuan D Chen L Webster J Fang AC Gene Prioritization of Resistant Rice Gene against Xanthomas oryzae pv. oryzae by Using Text Mining TechnologiesBiomed Res Int2013 2013853043

    Not in our library10.1155/2013/853043

  78. 78.

    Mattick JS Mehler MF RNA editing, DNA recoding and the evolution of human cognitionTrends Neurosci2008 31227233

    Not in our library10.1016/j.tins.2008.02.003

  79. 79.

    Mehler MF Mattick JS Noncoding RNAs and RNA editing in brain development, functional diversification, and neurological diseasePhysiol Rev2007 87799823

    Not in our library10.1152/physrev.00036.2006

  80. 80.

    Hertz L Bioenergetics of cerebral ischemia: a cellular perspectiveNeuropharmacology2008 55289309

    Not in our library10.1016/j.neuropharm.2008.05.023

  81. 81.

    Qureshi IA Mattick JS Mehler MF Long non-coding RNAs in nervous system function and diseaseBrain Res2010 13382035

    Not in our library10.1016/j.brainres.2010.03.110

  82. 82.

    Qureshi IA Mehler MF Emerging roles of non-coding RNAs in brain evolution, development, plasticity and diseaseNat Rev Neurosci2012 13528541

    Not in our library10.1038/nrn3234

  83. 83.
  84. 84.

    Ng SY Johnson R Stanton LW Human long non-coding RNAs promote pluripotency and neuronal differentiation by association with chromatin modifiers and transcription factorsEMBO J2012 31522533

    Not in our library10.1038/emboj.2011.459

  85. 85.

    Sobocki T Sobocka MB Babinska A Ehrlich YH Banerjee P Kornecki E Genomic structure, organization and promoter analysis of the human F11R/F11 receptor/junctional adhesion molecule-1/JAM-AGene2006 366128144

    Not in our library10.1016/j.gene.2005.08.025

  86. 86.

    Riccardo S Tortoriello G Giordano E Turano M Furia M The coding/non-coding overlapping architecture of the gene encoding the Drosophila pseudouridine synthaseBMC Mol Biol2007 815

    Not in our library10.1186/1471-2199-8-15

  87. 87.

    Qureshi IA Mehler MF The emerging role of epigenetics in stroke: II. RNA regulatory circuitryArch Neurol2010 6714351441

    Not in our library10.1001/archneurol.2010.300

  88. 88.

    Latos PA Pauler FM Koerner MV Şenergin HB Hudson QJ Stocsits RR Allhoff W Stricker SH Klement RM Warczok KE Aumayr K Pasierbek P Barlow DP Airn transcriptional overlap, but not its lncRNA products, induces imprinted Igf2r silencingScience2012 33814691472

    Not in our library10.1126/science.1228110

  89. 89.
  90. 90.
  91. 91.

    Sleutels F Zwart R Barlow DP The non-coding Air RNA is required for silencing autosomal imprinted genesNature2002 415810813

    Not in our library10.1038/415810a

  92. 92.

    Brockdorff N Ashworth A Kay GF Cooper P Smith S McCabe VM Norris DP Penny GD Patel D Rastan S Conservation of position and exclusive expression of mouse Xist from the inactive X chromosomeNature1991 351329331

    Not in our library10.1038/351329a0

  93. 93.

    Penny GD Kay GF Sheardown SA Rastan S Brockdorff N Requirement for Xist in X chromosome inactivationNature1996 379131137

    Not in our library10.1038/379131a0

  94. 94.

    Brockdorff N Ashworth A Kay GF McCabe VM Norris DP Cooper PJ Swift S Rastan S The product of the mouse Xist gene is a 15 kb inactive X-specific transcript containing no conserved ORF and located in the nucleusCell1992 71515526

    Not in our library10.1016/0092-8674(92)90519-i

  95. 95.

    Rinn JL Kertesz M Wang JK Squazzo SL Xu X Brugmann SA Goodnough LH Helms JA Farnham PJ Segal E Chang HY Functional demarcation of active and silent chromatin domains in human HOX loci by noncoding RNAsCell2007 12913111323

    Not in our library10.1016/j.cell.2007.05.022

  96. 96.

    Mancini-Dinardo D Steele SJ Levorse JM Ingram RS Tilghman SM Elongation of the Kcnq1ot1 transcript is required for genomic imprinting of neighboring genesGenes Dev2006 2012681282

    Not in our library10.1101/gad.1416906

  97. 97.

    Liang M Li W Tian H Hu T Wang 3 Lin Y Li Y Huang H Sun F Sequential expression of long noncoding RNA as mRNA gene expression in specific stages of mouse spermatogenesisSci Rep2014 45966

    Not in our library10.1038/srep05966

  98. 98.

    Tani H Mizutani R Salam KA Tano K Ijiri K Wakamatsu A Isogai T Suzuki Y Akimitsu N Genome-wide determination of RNA stability reveals hundreds of short-lived noncoding transcripts in mammalsGenome Res2012 22947956

    Not in our library10.1101/gr.130559.111

  99. 99.

    Mata J Genome-wide mapping of polyadenylation sites in fission yeast reveals widespread alternative polyadenylationRNA Biol2013 1014071414

    Not in our library10.4161/rna.25758

  100. 100.

    Russell PJ iGenetics. 3rd ed. San Francisco: Pearson Benjamin CummingsExpert Opin Biol2010 12217230

    Not in our library

  101. 101.

    Saffhill R Itzhaki RF Accessibility of chromatin to DNA polymerase I and location of the F1 histoneNucleic Acids Res1975 2113119

    Not in our library10.1093/nar/2.1.113

  102. 102.

    Bustin M Arrangement of histones in chromatinNat New Biol1973 245207209

    Not in our library10.1038/newbio245207a0

  103. 103.

    Prioleau MN Huet J Sentenac A Méchali M Competition between chromatin and transcription complex assembly regulates gene expression during early developmentCell1994 77439449

    Not in our library10.1016/0092-8674(94)90158-9

  104. 104.

    Voss TC John S Hager GL Single-cell analysis of glucocorticoid receptor action reveals that stochastic post-chromatin association mechanisms regulate ligand-specific transcriptionMol Endocrinol2006 2026412655

    Not in our library10.1210/me.2006-0091

  105. 105.

    Koike K Kasamatsu A Iyoda M Saito Y Kouzu Y Koike H Sakamoto Y Ogawara K Tanzawa H Uzawa K High prevalence of epigenetic inactivation of the human four and a half LIM domains 1 gene in human oral cancerInt J Oncol2013 42141150

    Not in our library10.3892/ijo.2012.1677

  106. 106.

    Chang CP Bruneau BG Epigenetics and cardiovascular developmentAnnu Rev Physiol2012 744168

    Not in our library10.1146/annurev-physiol-020911-153242

  107. 107.

    Wutz A Epigenetic regulation of stem cells: the role of chromatin in cell differentiationAdv Exp Med Biol2013 786307328

    Not in our library10.1007/978-94-007-6621-1_17

  108. 108.

    Kouzarides T Chromatin modifications and their functionCell2007 128693705

    Not in our library10.1016/j.cell.2007.02.005

  109. 109.

    Shiio Y Eisenman RN Histone sumoylation is associated with transcriptional repressionProc Natl Acad Sci U S A2003 1001322513230

    Not in our library10.1073/pnas.1735528100

  110. 110.

    Yang XJ Multisite protein modification and intramolecular signalingOncogene2005 2416531662

    Not in our library10.1038/sj.onc.1208173

  111. 111.

    Shilatifard A Chromatin modifications by methylation and ubiquitination: implications in the regulation of gene expressionAnnu Rev Biochem2006 75243269

    Not in our library10.1146/annurev.biochem.75.103004.142422

  112. 112.

    Xie W Ames RS Li H A cell-based high-throughput screening assay to measure cellular histone h3 lys27 trimethylation with a modified dissociation-enhanced lanthanide fluorescent immunoassayJ Biomol Screen2012 1799107

    Not in our library10.1177/1087057111422378

  113. 113.

    Liu D Xu B Chen S Yang Y Zhang X Liu J Lu K Zhang L Liu C Zhao Y Jiang H Liu N Chen M Long non-coding RNAs and prostate cancerJ Nanosci Nanotechnol2013 1331863194

    Not in our library10.1166/jnn.2013.6870

  114. 114.
  115. 115.

    Khaitan D Dinger ME Mazar J Crawford J Smith MA Mattick JS Perera RJ The melanoma-upregulated long noncoding RNA SPRY4-IT1 modulates apoptosis and invasionCancer Res2011 7138523862

    Not in our library10.1158/0008-5472.can-10-4460

  116. 116.

    Mazar J DeBlasio D Govindarajan SS Zhang S Perera RJ Epigenetic regulation of microRNA-375 and its role in melanoma development in humansFEBS Lett2011 58524672476

    Not in our library10.1016/j.febslet.2011.06.025

  117. 117.

    Dudziec E Goepel JR Catto JW Global epigenetic profiling in bladder cancerEpigenomics2011 33545

    Not in our library10.2217/epi.10.71

  118. 118.

    Guil S Esteller M DNA methylomes, histone codes and miRNAs: tying it all togetherInt J Biochem Cell Biol2009 418795

    Not in our library10.1016/j.biocel.2008.09.005

  119. 119.
  120. 120.

    Mazar J Khaitan D DeBlasio D Zhong C Govindarajan SS Kopanathi S Zhang S Ray A Perera RJ Epigenetic regulation of microRNA genes and the role of miR-34b in cell invasion and motility in human melanomaPLoS One2011 6e24922

    Not in our library10.1371/journal.pone.0024922

  121. 121.

    Chen X He D Dong XD Dong F Wang J Wang L Tang J Hu DN Yan D Tu L MicroRNA-124a is epigenetically regulated and acts as a tumor suppressor by controlling multiple targets in uveal melanomaInvest Ophthalmol Vis Sci2013 5422482256

    Not in our library10.1167/iovs.12-10977

  122. 122.

    Kuphal S Martyn AC Pedley J Crowther LM Bonazzi VF Parsons PG Bosserhoff AK Hayward NK Boyle GM H-cadherin expression reduces invasion of malignant melanomaPigment Cell Melanoma Res2009 22296306

    Not in our library10.1111/j.1755-148x.2009.00568.x

  123. 123.

    Lopez-Serra P1 Esteller M DNA methylation-associated silencing of tumor-suppressor microRNAs in cancerOncogene2012 3116091622

    Not in our library10.1038/onc.2011.354

  124. 124.

    Hassel JC Sucker A Edler L Kurzen H Moll I Stresemann C Spieth K Mauch C Rass K Dummer R Schadendorf D MGMT gene promoter methylation correlates with tolerance of temozolomide treatment in melanoma but not with clinical outcomeBr J Cancer2010 103820826

    Not in our library10.1038/sj.bjc.6605796

  125. 125.

    Lujambio A Esteller M CpG island hypermethylation of tumor suppressor microRNAs in human cancerCell Cycle2007 614551459

    Not in our library

  126. 126.

    Csankovszki G Nagy A Jaenisch R Synergism of Xist RNA, DNA methylation, and histone hypoacetylation in maintaining X chromosome inactivationJ Cell Biol2001 153773784

    Not in our library10.1083/jcb.153.4.773

  127. 127.

    Brose RD Shin G McGuinness MC Schneidereith T Purvis S Dong GX Keefer J Spencer F Smith KD Activation of the stress proteome as a mechanism for small molecule therapeuticsHum Mol Genet2012 2142374252

    Not in our library10.1093/hmg/dds247

  128. 128.

    Liu N Parisien M Dai Q Zheng G He C Pan T Probing N6-methyladenosine RNA modification status at single nucleotide resolution in mRNA and long noncoding RNARNA2013 1918481856

    Not in our library10.1261/rna.041178.113

  129. 129.

    Hsieh CL In vivo activity of murine de novo methyltransferases, Dnmt3a and Dnmt3bMol Cell Biol1999 1982118218

    Not in our library10.1128/mcb.19.12.8211

  130. 130.

    Maquat LE Nonsense-mediated mRNA decay: splicing, translation and mRNP dynamicsNat Rev Mol Cell Biol2004 58999

    Not in our library10.1038/nrm1310

  131. 131.

    Lehmann U Hasemeier B Christgen M Müller M Römermann D Länger F Kreipe H Epigenetic inactivation of microRNA gene hsa-mir-9-1 in human breast cancerJ Pathol2008 2141724

    Not in our library10.1002/path.2251

  132. 132.

    Grady WM Parkin RK Mitchell PS Lee JH Kim YH Tsuchiya KD Washington MK Paraskeva C Willson JK Kaz AM Kroh EM Allen A Fritz BR Markowitz SD Tewari M Epigenetic silencing of the intronic microRNA hsa-miR-342 and its host gene EVL in colorectal cancerOncogene2008 2738803888

    Not in our library10.1038/onc.2008.10

  133. 133.

    Casadio V Molinari C Calistri D Tebaldi M Gunelli R Serra L Falcini F Zingaretti C Silvestrini R Amadori D Zoli W DNA Methylation profiles as predictors of recurrence in non muscle invasive bladder cancer: an MS-MLPA approachJ Exp Clin Cancer Res2013 3294

    Not in our library10.1186/1756-9966-32-94

  134. 134.

    Jung EJ Kim IS Lee EY Kang JE Lee SM Kim DC Kim JY Park ST Comparison of methylation profiling in cancerous and their corresponding normal tissues from korean patients with breast cancerAnn Lab Med2013 33431440

    Not in our library10.3343/alm.2013.33.6.431

  135. 135.

    Iscovich J Ackerman C Andreev H Pe'er J Steinitz R An epidemiological study of posterior uveal melanoma in Israel, 1961–1989Int J Cancer1995 61291295

    Not in our library10.1002/ijc.2910610302

  136. 136.

    Jeffery L Nakielny S Components of the DNA methylation system of chromatin control are RNA-binding proteinsJ Biol Chem2004 2794947949487

    Not in our library10.1074/jbc.m409070200

  137. 137.

    Robertson KD DNA methylation and human diseaseNat Rev Genet2005 6597610

    Not in our library10.1038/nrg1655

  138. 138.

    Bestor TH The DNA, methyltransferases of mammalsHum Mol Genet2000 923952402

    Not in our library10.1093/hmg/9.16.2395

  139. 139.

    Bird A DNA methylation patterns and epigenetic memoryGenes Dev2002 16621

    Not in our library10.1101/gad.947102

  140. 140.

    Okano M Bell DW Haber DA Li E DNA methyltransferases Dnmt3a and Dnmt3b are essential for de novo methylation and mammalian developmentCell1999 99247257

    Not in our library10.1016/s0092-8674(00)81656-6

  141. 141.

    Groth A Rocha W Verreault A Almouzni G Chromatin challenges during DNA replication and repairCell2007 128721733

    Not in our library10.1016/j.cell.2007.01.030

  142. 142.

    Mani S Szymańska K Cuenin C Zaridze D Balassiano K Lima SC Matos E Daudt A Koifman S Filho VW Menezes AM Curado MP Ferro G Vaissière T Sylla BS Tommasino M Pinto LF Boffetta P Hainaut P Brennan P Herceg Z DNA methylation changes associated with risk factors in tumors of the upper aerodigestive tractEpigenetics2012 7270277

    Not in our library10.4161/epi.7.3.19306

  143. 143.

    da Rocha ST Boeva V Escamilla-Del-Arenal M Ancelin K Granier C Matias NR Sanulli S Chow J Schulz E Picard C Kaneko S Helin K Reinberg D Stewart AF Wutz A Margueron R Heard E Jarid2 Is Implicated in the Initial Xist-Induced Targeting of PRC2 to the Inactive X ChromosomeMol Cell2014 53301316

    Not in our library10.1016/j.molcel.2014.01.002

  144. 144.
  145. 145.

    Berghoff EG Clark MF Chen S Cajigas I Leib DE Kohtz JD Evf2 (Dlx6as) lncRNA regulates ultraconserved enhancer methylation and the differential transcriptional control of adjacent genesDevelopment2013 14044074416

    Not in our library10.1242/dev.099390

  146. 146.
  147. 147.

    Liu Q Huang J Zhou N Zhang Z Zhang A Lu Z Wu F Mo YY LncRNA loc285194 is a p53-regulated tumor suppressorNucleic Acids Res2013 4149764987

    Not in our library10.1093/nar/gkt182

  148. 148.

    Yang F Huo XS Yuan SX Zhang L Zhou WP Wang F Sun SH Repression of the long noncoding RNA-LET by histone deacetylase 3 contributes to hypoxia-mediated metastasisMol Cell2013 4910831096

    Not in our library10.1016/j.molcel.2013.01.010

  149. 149.

    Yang F Zhang L Huo XS Yuan JH Xu D Yuan SX Zhu N Zhou WP Yang GS Wang YZ Shang JL Gao CF Zhang FR Wang F Sun SH Long noncoding RNA high expression in hepatocellular carcinoma facilitates tumor growth through enhancer of zeste homolog 2 in humansHepatology2011 5416791689

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    Li Z Chao TC Chang KY Lin N Patil VS Shimizu C Head SR Burns JC Rana TM The long noncoding RNA THRIL regulates TNFalpha expression through its interaction with hnRNPLProc Natl Acad Sci U S A2014 11110021007

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    Carpenter S Aiello D Atianand MK Ricci EP Gandhi P Hall LL Byron M Monks B Henry-Bezy M Lawrence JB O'Neill LA Moore MJ Caffrey DR Fitzgerald KA A long noncoding RNA mediates both activation and repression of immune response genesScience2013 341789792

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    Shani V Bromberg Y Sperling O Zoref-Shani E Involvement of Src tyrosine kinases (SFKs) and of focal adhesion kinase (FAK) in the injurious mechanism in rat primary neuronal cultures exposed to chemical ischemiaJ Mol Neurosci2009 375059

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    Gumireddy K Li A Yan J Setoyama T Johannes GJ Orom UA Tchou J Liu Q Zhang L Speicher DW Calin GA Huang Q Identification of a long non-coding RNA-associated RNP complex regulating metastasis at the translational stepEMBO J2013 3226722684

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    Zhang J Zhang P Wang L Piao HL Ma L Long non-coding RNA HOTAIR in carcinogenesis and metastasisActa Biochim Biophys Sin (Shanghai)2014 4615

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    Liu F Marquardt S Lister C Swiezewski S Dean C Targeted 3’ processing of antisense transcripts triggers Arabidopsis FLC chromatin silencingScience2010 3279497

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    Ohhata T Hoki Y Sasaki H Sado T Crucial role of antisense transcription across the Xist promoter in Tsix-mediated Xist chromatin modificationDevelopment2008 135227235

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    Masri S Sassone-Corsi P Sirtuins and the circadian clock: Bridging chromatin and metabolismSci Signal2014 7re6

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    Aravind L Iyer LM The SWIRM domain: a conserved module found in chromosomal proteins points to novel chromatin-modifying activitiesGenome Biol2002 3RESEARCH0039

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    Khalil AM Rinn JL RNA-protein interactions in human health and diseaseSemin Cell Dev Biol2011 22359365

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  178. 178.

    Heinlein CA Chang C Androgen receptor (AR) coregulators: an overviewEndocr Rev2002 23175200

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  179. 179.

    Hassan AH Neely KE Vignali M Reese JC Workman JL Promoter targeting of chromatin-modifying complexesFront Biosci2001 6D1054D1064

    Not in our library10.2741/hassan

  180. 180.

    Bingham AJ Ooi L Kozera L White E Wood IC The repressor element 1-silencing transcription factor regulates heart-specific gene expression using multiple chromatin-modifying complexesMol Cell Biol2007 2740824092

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  181. 181.

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  182. 182.
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    Nagano T Mitchell JA Sanz LA Pauler FM Ferguson-Smith AC Feil R Fraser P The Air noncoding RNA epigenetically silences transcription by targeting G9a to chromatinScience2008 32217171720

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  184. 184.

    Xia L Zhang D Du R Pan Y Zhao L Sun S Hong L Liu J Fan D miR-15b and miR-16 modulate multidrug resistance by targeting BCL2 in human gastric cancer cellsInt J Cancer2008 123372379

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  185. 185.

    Yan D Dong XD Chen X Yao S Wang L Wang J Wang C Hu DN Qu J Tu L Role of microRNA-182 in posterior uveal melanoma: regulation of tumor development through MITF, BCL2 and cyclin D2PLoS One2012 7e40967

    Not in our library10.1371/journal.pone.0040967

  186. 186.

    Huo JS Zambidis ET Pivots of pluripotency: the roles of non-coding RNA in regulating embryonic and induced pluripotent stem cellsBiochim Biophys Acta2013 183023852394

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  187. 187.

    Hawkins PG Morris KV Transcriptional regulation of Oct4 by a long non-coding RNA antisense to Oct4-pseudogene 5Transcription2010 1165175

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  189. 189.

    Braconi C Kogure T Valeri N Huang N Nuovo G Costinean S Negrini M Miotto E Croce CM Patel T microRNA-29 can regulate expression of the long non-coding RNA gene MEG3 in hepatocellular cancerOncogene2011 3047504756

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  190. 190.

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    Bönsch D Lenz B Fiszer R Frieling H Kornhuber J Bleich S Lowered DNA methyltransferase (DNMT-3b) mRNA expression is associated with genomic DNA hypermethylation in patients with chronic alcoholismJ Neural Transm2006 11312991304

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    Yang L Lin C Jin C Yang JC Tanasa B Li W Merkurjev D Ohgi KA Meng D Zhang J Evans CP Rosenfeld MG lncRNA-dependent mechanisms of androgen-receptor-regulated gene activation programsNature2013 500598602

    Not in our library10.1038/nature12451

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    Liu SP Yang JX Cao DY Shen K Identification of differentially expressed long non-coding RNAs in human ovarian cancer cells with different metastatic potentialsCancer Biol Med2013 10138141

    Not in our library10.7497/j.issn.2095-3941.2013.03.003

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