Many human large intergenic noncoding RNAs associate with chromatin-modifying complexes and affect gene expression.
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ABSTRACT:
SUBMITTER: Khalil AM
PROVIDER: S-EPMC2704857 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:We recently showed that the mammalian genome encodes more than a thousand large intergenic non-coding RNAs (lincRNAs) that are clearly conserved across mammals and thus functional. Gene expression patterns have implicated these lincRNAs in diverse biological processes including cell cycle regulation, immune surveillance, and embryonic stem cell pluripotency. However, the mechanism by which these lincRNAs function is unknown. Here, we expand the catalog of human lincRNAs to ~3300 by analyzing chromatin-state maps of various human cell types. Inspired by the observation that the well-characterized lincRNA HOTAIR bind the Polycomb Repressive Complex 2 (PRC2), we tested whether many lincRNAs are physically associated with PRC2. Remarkably, we observe that ~20% of lincRNAs expressed in various cell types are bound by PRC2, and that additional lincRNAs are bound by other chromatin-modifying complexes. Moreover, we show that siRNA-mediated depletion of certain lincRNAs associated with PRC2 leads to changes in gene expression and that the upregulated genes are enriched for those normally silenced by PRC2. We propose a model in which some lincRNAs guide chromatin–modifying complexes to specific genomic loci to regulate gene expression. siRNA-mediated lincRNA knockdown siRNAs targeting specific lincRNAs were transected into human fibroblasts. Non-targeting siRNAs were used as controls. Both of these experiment types were hybridized to Affymetrix gene expression arrays. PRC2 RIP-Chip The PRC2 complex was immunoprecipitated using antibodies targetting Suz12 and the associated RNA was hybridized to Nimblegen tiling arrays representing lincRNAs. In parallel an IgG IP was performed and hybridized to the same NG arrays. RIP was performed for PRC2 and hybridized using a Cy3 label. In parallel, RIP was performed using IGG and labelled with Cy5 PRC2 RIP-Chip (dye swap) The PRC2 complex was immunoprecipitated using antibodies targetting Suz12 and the associated RNA was hybridized to Nimblegen tiling arrays representing lincRNAs. In parallel an IgG IP was performed and hybridized to the same NG arrays. RIP was performed for PRC2 and hybridized using a Cy5 label. In parallel, RIP was performed using IGG and labelled with Cy3 PRC2 RIP-Chip (no proteins) The PRC2 complex was immunoprecipitated using antibodies targetting Suz12 and the associated RNA was hybridized to Nimblegen tiling arrays representing lincRNAs. In parallel an IgG IP was performed and hybridized to the same NG arrays. RIP was performed for PRC2 and hybridized using a Cy3 label. In parallel, RIP was performed using IGG and labelled with Cy5 COREST RIP-Chip The COREST complex was immunoprecipitated using antibodies targetting COREST and the associated RNA was hybridized to Nimblegen tiling arrays representing lincRNAs. In parallel an IgG IP was performed and hybridized to the same NG arrays. RIP was performed for COREST and hybridized using a Cy3 label. In parallel, RIP was performed using IGG and labelled with Cy5 H3K27me3 and H3K4me2 modified histones RIP-Chip The H3K27me3 and H3K4me2 modified histones were immunoprecipitated using antibodies targetting COREST and the associated RNA was hybridized to Nimbelgen tiling arrays representing lincRNAs. In parallel an IgG IP was performed and hybridized to the same NG arrays. RIP was performed for COREST and hybridized using a Cy3 label. In parallel, RIP was performed using IGG and labelled with Cy5 Human lincRNA expression Human lincRNAs were profiled in HeLa, Lung FB, and Foot FB. In addition, nuclear and cytoplasmic fractions were taken in HeLa cells Total RNA was extracted from HeLa, Foot, and Lung cells and hybridized to NG tiling array. In addition, the nucleus was fractionated and RNA was hybridized to an array.
2009-07-09 | E-GEOD-16226 | biostudies-arrayexpress
Project description:We recently showed that the mammalian genome encodes more than a thousand large intergenic non-coding RNAs (lincRNAs) that are clearly conserved across mammals and thus functional. Gene expression patterns have implicated these lincRNAs in diverse biological processes including cell cycle regulation, immune surveillance, and embryonic stem cell pluripotency. However, the mechanism by which these lincRNAs function is unknown. Here, we expand the catalog of human lincRNAs to ~3300 by analyzing chromatin-state maps of various human cell types. Inspired by the observation that the well-characterized lincRNA HOTAIR bind the Polycomb Repressive Complex 2 (PRC2), we tested whether many lincRNAs are physically associated with PRC2. Remarkably, we observe that ~20% of lincRNAs expressed in various cell types are bound by PRC2, and that additional lincRNAs are bound by other chromatin-modifying complexes. Moreover, we show that siRNA-mediated depletion of certain lincRNAs associated with PRC2 leads to changes in gene expression and that the upregulated genes are enriched for those normally silenced by PRC2. We propose a model in which some lincRNAs guide chromatin–modifying complexes to specific genomic loci to regulate gene expression.
2009-07-09 | GSE16226 | GEO
Project description:ObjectiveTranscriptome profiling of human tissues has revealed thousands of long intergenic noncoding RNAs (lincRNAs) at loci identified through large-scale genome-wide studies for complex cardiometabolic traits. This raises the question of whether genetic variation at nonconserved lincRNAs has any systematic association with complex disease, and if so, how different this pattern is from conserved lincRNAs. We evaluated whether the associations between nonconserved lincRNAs and 8 complex cardiometabolic traits resemble or differ from the pattern of association for conserved lincRNAs. Approach and Results: Our investigation of over 7000 lincRNA annotations from GENCODE Release 33-GRCh38.p13 for complex trait genetic associations leveraged several large, established meta-analyses genome-wide association study summary data resources, including GIANT (Genetic Investigation of Anthropometric Traits), UK Biobank, GLGC (Global Lipids Genetics Consortium), Cardiogram (Coronary Artery Disease Genome Wide Replication and Meta-Analysis), and DIAGRAM (Diabetes Genetics Replication and Meta-Analysis)/DIAMANTE (Diabetes Meta-Analysis of Trans-Ethnic Association Studies). These analyses revealed that (1) nonconserved lincRNAs associate with a range of cardiometabolic traits at a rate that is generally consistent with conserved lincRNAs; (2) these findings persist across different definitions of conservation; and (3) overall across all cardiometabolic traits, approximately one-third of genome-wide association study-associated lincRNAs are nonconserved, and this increases to about two-thirds using a more stringent definition of conservation.ConclusionsThese findings suggest that the traditional notion of conservation driving prioritization for functional and translational follow-up of complex cardiometabolic genomic discoveries may need to be revised in the context of the abundance of nonconserved long noncoding RNAs in the human genome and their apparent predilection to associate with complex cardiometabolic traits.
| S-EPMC7886007 | biostudies-literature
Project description:Long intergenic noncoding RNAs (lincRNAs) are a class of independently transcribed molecules longer than 200 nucleotides that do not overlap known protein-coding genes. LincRNAs have diverse roles in gene expression and participate in a spectrum of biological processes. Dysregulation of lincRNA expression can abrogate cellular homeostasis, cell differentiation, and development and can also deregulate the immune and nervous systems. A growing body of literature indicates their important and multifaceted roles in the pathogenesis of several different diseases. Furthermore, certain lincRNAs can be considered potential therapeutic targets and valuable diagnostic or prognostic biomarkers capable of predicting the onset of a disease, its degree of activity, or the progression phase. In this review, we discuss possible mechanisms and molecular functions of lincRNAs in the pathogenesis of selected autoimmune and neurodegenerative disorders: multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, Huntington's disease, Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis. This summary can provide new ideas for future research, diagnosis, and treatment of these highly prevalent and devastating diseases.
| S-EPMC9395482 | biostudies-literature
Project description:Long intergenic noncoding RNAs (lincRNAs) play important roles in disease, but the vast majority of these transcripts remain uncharacterized. We defined a set of 54 944 human lincRNAs by drawing on four publicly available lincRNA datasets, and annotated ∼2.5 million single nucleotide polymorphisms (SNPs) from each of 15 cardiometabolic genome-wide association study datasets into these lincRNAs. We identified hundreds of lincRNAs with at least one trait-associated SNP: 898 SNPs in 343 unique lincRNAs at 5% false discovery rate, and 469 SNPs in 146 unique lincRNAs meeting Bonferroni-corrected P < 0.05. An additional 64 trait-associated lincRNAs were identified using a class-level testing strategy at Bonferroni-corrected P < 0.05. To better understand the genomic context and prioritize trait-associated lincRNAs, we examined the pattern of linkage disequilibrium between SNPs in the lincRNAs and SNPs that met genome-wide-significance in the region (±500 kb of lincRNAs). A subset of the lincRNA-trait association findings was replicated in independent Genome-wide association studies data from the Pakistan Risk of Myocardial Infarction Study study. For trait-associated lincRNAs, we also investigated synteny and conservation relative to mouse, expression patterns in five cardiometabolic-relevant tissues, and allele-specific expression in RNA sequencing data for adipose tissue and leukocytes. Finally, we revealed a functional role in human adipocytes for linc-NFE2L3-1, which is expressed in adipose and is associated with waist-hip ratio adjusted for BMI. This comprehensive profile of trait-associated lincRNAs provides novel insights into disease mechanism and serves as a launching point for interrogation of the biology of specific lincRNAs in cardiometabolic disease.
| S-EPMC5181595 | biostudies-literature
Project description:Large intergenic noncoding RNAs (lincRNAs) have been recognized in recent years to constitute a significant portion of the mammalian transcriptome, yet their biological functions remain largely elusive. This is partly due to an incomplete annotation of tissue-specific lincRNAs in essential model organisms, particularly in mice, which has hindered the genetic annotation and functional characterization of these novel transcripts. In this report, we performed ab initio assembly of 1.9 billion tissue-specific RNA-sequencing reads across six tissue types, and identified 3,965 novel expressed lincRNAs in mice. Combining these with 6,606 documented lincRNAs, we established a comprehensive catalog of 10,571 transcribed lincRNAs. We then systemically analyzed all mouse lincRNAs to reveal that some of them are evolutionally conserved and that they exhibit striking tissue-specific expression patterns. We also discovered that mouse lincRNAs carry unique genomic signatures, and that their expression level is correlated with that of neighboring protein-coding transcripts. Finally, we predicted that a large portion of tissue-specific lincRNAs are functionally associated with essential biological processes including the cell cycle and cell development, and that they could play a key role in regulating tissue development and functionality. Our analyses provide a framework for continued discovery and annotation of tissue-specific lincRNAs in model organisms, and our transcribed mouse lincRNA catalog will serve as a roadmap for functional analyses of lincRNAs in genetic mouse models.
| S-EPMC3741367 | biostudies-literature
Project description:Large intergenic noncoding RNAs (lincRNAs) are emerging as key regulators of diverse cellular processes. Determining the function of individual lincRNAs remains a challenge. Recent advances in RNA sequencing (RNA-seq) and computational methods allow for an unprecedented analysis of such transcripts. Here, we present an integrative approach to define a reference catalog of >8000 human lincRNAs. Our catalog unifies previously existing annotation sources with transcripts we assembled from RNA-seq data collected from ?4 billion RNA-seq reads across 24 tissues and cell types. We characterize each lincRNA by a panorama of >30 properties, including sequence, structural, transcriptional, and orthology features. We found that lincRNA expression is strikingly tissue-specific compared with coding genes, and that lincRNAs are typically coexpressed with their neighboring genes, albeit to an extent similar to that of pairs of neighboring protein-coding genes. We distinguish an additional subset of transcripts that have high evolutionary conservation but may include short ORFs and may serve as either lincRNAs or small peptides. Our integrated, comprehensive, yet conservative reference catalog of human lincRNAs reveals the global properties of lincRNAs and will facilitate experimental studies and further functional classification of these genes.
| S-EPMC3185964 | biostudies-literature
Project description:During lytic replication of Kaposi's sarcoma-associated herpesvirus (KSHV), a nuclear viral long noncoding RNA known as PAN RNA becomes the most abundant polyadenylated transcript in the cell. Knockout or knockdown of KSHV PAN RNA results in loss of late lytic viral gene expression and, consequently, reduction of progeny virion release from the cell. Here, we demonstrate that knockdown of PAN RNA from the related Rhesus macaque rhadinovirus (RRV) phenocopies that of KSHV PAN RNA. These two PAN RNA homologs, although lacking significant nucleotide sequence conservation, can functionally substitute for each other to rescue phenotypes associated with the absence of PAN RNA expression. Because PAN RNA is exclusively nuclear, previous studies suggested that it directly interacts with host and viral chromatin to modulate gene expression. We studied KSHV and RRV PAN RNA homologs using capture hybridization analysis of RNA targets (CHART) and observed their association with host chromatin, but the loci differ between PAN RNA homologs. Accordingly, we find that KSHV PAN RNA is undetectable in chromatin following cell fractionation. Thus, modulation of gene expression at specific chromatin loci appears not to be the primary, nor the pertinent function of this viral long noncoding RNA. PAN RNA represents a cautionary tale for the investigation of RNA association with chromatin whereby cross-linking of DNA spatially adjacent to an abundant nuclear RNA gives the appearance of specific interactions. Similarly, PAN RNA expression does not affect viral transcription factor complex expression or activity, which is required for generation of the late lytic viral mRNAs. Rather, we provide evidence for an alternative model of PAN RNA function whereby knockdown of KSHV or RRV PAN RNA results in compromised nuclear mRNA export thereby reducing the cytoplasmic levels of viral mRNAs available for production of late lytic viral proteins.
| S-EPMC6233925 | biostudies-literature
Project description:BACKGROUND:Mammalian transcriptomes contain thousands of long noncoding RNAs (lncRNAs). Some lncRNAs originate from intragenic enhancers which, when active, behave as alternative promoters producing transcripts that are processed using the canonical signals of their host gene. We have followed up this observation by analyzing intergenic lncRNAs to determine the extent to which they might also originate from intergenic enhancers. RESULTS:We integrated high-resolution maps of transcriptional initiation and transcription to annotate a conservative set of intergenic lncRNAs expressed in mouse erythroblasts. We subclassified intergenic lncRNAs according to chromatin status at transcriptional initiation regions, defined by relative levels of histone H3K4 mono- and trimethylation. These transcripts are almost evenly divided between those arising from enhancer-associated (elncRNA) or promoter-associated (plncRNA) elements. These two classes of 5' capped and polyadenylated RNA transcripts are indistinguishable with regard to their length, number of exons or transcriptional orientation relative to their closest neighboring gene. Nevertheless, elncRNAs are more tissue-restricted, less highly expressed and less well conserved during evolution. Of considerable interest, we found that expression of elncRNAs, but not plncRNAs, is associated with enhanced expression of neighboring protein-coding genes during erythropoiesis. CONCLUSIONS:We have determined globally the sites of initiation of intergenic lncRNAs in erythroid cells, allowing us to distinguish two similarly abundant classes of transcripts. Different correlations between the levels of elncRNAs, plncRNAs and expression of neighboring genes suggest that functional lncRNAs from the two classes may play contrasting roles in regulating the transcript abundance of local or distal loci.
| S-EPMC4054604 | biostudies-literature
Project description:BackgroundOver 10,000 long intergenic non-coding RNAs (lincRNAs) have been identified in the human genome. Some have been well characterized and known to participate in various stages of gene regulation. In the post-transcriptional process, another class of well-known small non-coding RNA, or microRNA (miRNA), is very active in inhibiting mRNA. Though similar features between mRNA and lincRNA have been revealed in several recent studies, and a few isolated miRNA-lincRNA relationships have been observed. Despite these advances, the comprehensive miRNA regulation pattern of lincRNA has not been clarified.MethodsIn this study, we investigated the possible interaction between the two classes of non-coding RNAs. Instead of using the existing long non-coding database, we employed an ab initio method to annotate lincRNAs expressed in a group of normal breast tissues and breast tumors.ResultsApproximately 90 lincRNAs show strong reverse expression correlation with miRNAs, which have at least one predicted target site presented. These target sites are statistically more conserved than their neighboring genetic regions and other predicted target sites. Several miRNAs that target to these lincRNAs are known to play an essential role in breast cancer.ConclusionSimilar to inhibiting mRNAs, miRNAs show potential in promoting the degeneration of lincRNAs. Breast-cancer-related miRNAs may influence their target lincRNAs resulting in differential expression in normal and malignant breast tissues. This implies the miRNA regulation of lincRNAs may be involved in the regulatory process in tumor cells.
| S-EPMC3552696 | biostudies-literature