MicroRNA (miRNA) play a major role in the post-transcriptional regulation of gene expression. In mammals most miRNA derive from the introns of protein coding genes where they exist as hairpin structures in the primary gene transcript, synthesized by RNA polymerase II (Pol II). These are cleaved co-transcriptionally by the Microprocessor complex, comprising DGCR8 and the RNase III endonuclease Drosha, to release the precursor (pre-)miRNA hairpin, so generating both miRNA and spliced messenger RNA1-4. However, a substantial minority of miRNA originate from Pol II-synthesized long non coding (lnc) RNA where transcript processing is largely uncharacterized5. Here, we show that most lnc-pri-miRNA do not use the canonical cleavage and polyadenylation (CPA) transcription termination pathway6, but instead use Microprocessor cleavage both to release pre-miRNA and terminate transcription. We present a detailed characterization of one such lnc-pri-miRNA that generates the highly expressed liver-specific miR-1227. Genome-wide analysis then reveals that Microprocessor-mediated transcription termination is commonly used by lnc-pri-miRNA but not by protein coding miRNA genes. This identifies a fundamental difference between lncRNA and pre-mRNA processing. Remarkably, inactivation of the Microprocessor can lead to extensive transcriptional readthrough of lnc-pri-miRNA, resulting in inhibition of downstream genes by transcriptional interference. Consequently we define a novel RNase III-mediated, polyadenylation-independent mechanism of Pol II transcription termination in mammalian cells. Overall design: Chromatin associated RNA-seq from sicntrl,siDrosha,siDGCR8 treated Hela cells. Same for sicntrl and siDGCR8 from Huh7 cells. Nuclear polyA + and polyA- RNA-seq from sicntrl and siDGCR8 in HeLa cells. Chromatin associated RNA-seq from siDicer treated Hela cells.
Microprocessor mediates transcriptional termination of long noncoding RNA transcripts hosting microRNAs.
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View SamplesNumerous long intervening non-coding RNA (lincRNA) are generated from the mammalian genome by RNA polymerase II (Pol II) transcription. Although multiple functions have been ascribed to lincRNA, their synthesis and turnover remain poorly characterised. Here we define systematic differences in transcription and RNA processing between protein-coding and lincRNA genes in human HeLa cells. This is based on a range of nascent transcriptomic approaches applied to different nuclear fractions, including mammalian native elongating transcript sequencing (mNET-seq). Notably mNET-seq patterns specific for different Pol II CTD phosphorylation states reveal weak co-transcriptional splicing and poly(A) signal independent Pol II termination on lincRNA as compared to pre-mRNA. In addition, lincRNA are mostly restricted to chromatin where they are co-transcriptionally degraded by the RNA exosome. We also show that a lincRNA specific co-transcriptional RNA cleavage mechanism acts to induce premature termination. In effect functional lincRNA must escape from this targeted nuclear surveillance process. Overall design: We employed CTD phospho specific mNET-Seq with pla-B splicing inhibitor and RNA processing factors knockdown (DGCR8, Dicer1, EXOSC3 and CPSF73 proteins). mNET-seq experiments with 1% Empigen detergent treatment were performed to separate Pol II-associated complex from Pol II. We also analyzed subcellur RNA and pA+ and pA- nucleoplasm RNA libraries for RNA processing efficiency and the turnover. There are 4 raw files come from an illumina experiment (per sample), produced in 2 lanes. They were all mapped together.
Distinctive Patterns of Transcription and RNA Processing for Human lincRNAs.
Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Gene expression profiles of prostate cancer reveal involvement of multiple molecular pathways in the metastatic process.
Age, Specimen part, Race
View SamplesProstate cancer is characterized by heterogeneity in the clinical course that often does not to correlate with morphologic features of the tumor. Metastasis reflects the most adverse outcome of prostate cancer, and to date there are no reliable morphologic features or serum biomarkers that can reliably predict which patients are at higher risk of developing metastatic disease. Understanding the differences in the biology of metastatic and organ confined primary tumors is essential for developing new prognostic markers and therapeutic targets. Using Affymetrix oligonucleotide arrays, we analyzed gene expression profiles of 24 androgen-ablation resistant metastatic samples obtained from 4 patients and a previously published dataset of 64 primary prostate tumor samples. Differential gene expression was analyzed after removing potentially uninformative stromal genes, addressing the differences in cellular content between primary and metastatic tumors. The metastatic samples are highly heterogeneous in expression; however, differential expression analysis shows that 415 genes are upregulated and 364 genes are downregulated at least 2 fold in every patient with metastasis. The expression profile of metastatic samples reveals changes in expression of a unique set of genes representing both the androgen ablation related pathways and other metastasis related gene networks such as cell adhesion, bone remodeling and cell cycle. The differentially expressed genes include metabolic enzymes, transcription factors such as Forkhead Box M1 (FoxM1) and cell adhesion molecules such as Osteopontin (SPP1). We hypothesize that these genes have a role in the biology of metastatic disease and that they represent potential therapeutic targets for prostate cancer.
Gene expression profiles of prostate cancer reveal involvement of multiple molecular pathways in the metastatic process.
Specimen part
View SamplesProstate cancer is characterized by heterogeneity in the clinical course that often does not to correlate with morphologic features of the tumor. Metastasis reflects the most adverse outcome of prostate cancer, and to date there are no reliable morphologic features or serum biomarkers that can reliably predict which patients are at higher risk of developing metastatic disease. Understanding the differences in the biology of metastatic and organ confined primary tumors is essential for developing new prognostic markers and therapeutic targets. Using Affymetrix oligonucleotide arrays, we analyzed gene expression profiles of 24 androgen-ablation resistant metastatic samples obtained from 4 patients and a previously published dataset of 64 primary prostate tumor samples. Differential gene expression was analyzed after removing potentially uninformative stromal genes, addressing the differences in cellular content between primary and metastatic tumors. The metastatic samples are highly heterogeneous in expression; however, differential expression analysis shows that 415 genes are upregulated and 364 genes are downregulated at least 2 fold in every patient with metastasis. The expression profile of metastatic samples reveals changes in expression of a unique set of genes representing both the androgen ablation related pathways and other metastasis related gene networks such as cell adhesion, bone remodeling and cell cycle. The differentially expressed genes include metabolic enzymes, transcription factors such as Forkhead Box M1 (FoxM1) and cell adhesion molecules such as Osteopontin (SPP1). We hypothesize that these genes have a role in the biology of metastatic disease and that they represent potential therapeutic targets for prostate cancer.
Gene expression profiles of prostate cancer reveal involvement of multiple molecular pathways in the metastatic process.
Specimen part
View SamplesProstate cancer is characterized by heterogeneity in the clinical course that often does not to correlate with morphologic features of the tumor. Metastasis reflects the most adverse outcome of prostate cancer, and to date there are no reliable morphologic features or serum biomarkers that can reliably predict which patients are at higher risk of developing metastatic disease. Understanding the differences in the biology of metastatic and organ confined primary tumors is essential for developing new prognostic markers and therapeutic targets. Using Affymetrix oligonucleotide arrays, we analyzed gene expression profiles of 24 androgen-ablation resistant metastatic samples obtained from 4 patients and a previously published dataset of 64 primary prostate tumor samples. Differential gene expression was analyzed after removing potentially uninformative stromal genes, addressing the differences in cellular content between primary and metastatic tumors. The metastatic samples are highly heterogeneous in expression; however, differential expression analysis shows that 415 genes are upregulated and 364 genes are downregulated at least 2 fold in every patient with metastasis. The expression profile of metastatic samples reveals changes in expression of a unique set of genes representing both the androgen ablation related pathways and other metastasis related gene networks such as cell adhesion, bone remodeling and cell cycle. The differentially expressed genes include metabolic enzymes, transcription factors such as Forkhead Box M1 (FoxM1) and cell adhesion molecules such as Osteopontin (SPP1). We hypothesize that these genes have a role in the biology of metastatic disease and that they represent potential therapeutic targets for prostate cancer.
Gene expression profiles of prostate cancer reveal involvement of multiple molecular pathways in the metastatic process.
Specimen part
View SamplesProstate cancer is characterized by heterogeneity in the clinical course that often does not to correlate with morphologic features of the tumor. Metastasis reflects the most adverse outcome of prostate cancer, and to date there are no reliable morphologic features or serum biomarkers that can reliably predict which patients are at higher risk of developing metastatic disease. Understanding the differences in the biology of metastatic and organ confined primary tumors is essential for developing new prognostic markers and therapeutic targets. Using Affymetrix oligonucleotide arrays, we analyzed gene expression profiles of 24 androgen-ablation resistant metastatic samples obtained from 4 patients and a previously published dataset of 64 primary prostate tumor samples. Differential gene expression was analyzed after removing potentially uninformative stromal genes, addressing the differences in cellular content between primary and metastatic tumors. The metastatic samples are highly heterogeneous in expression; however, differential expression analysis shows that 415 genes are upregulated and 364 genes are downregulated at least 2 fold in every patient with metastasis. The expression profile of metastatic samples reveals changes in expression of a unique set of genes representing both the androgen ablation related pathways and other metastasis related gene networks such as cell adhesion, bone remodeling and cell cycle. The differentially expressed genes include metabolic enzymes, transcription factors such as Forkhead Box M1 (FoxM1) and cell adhesion molecules such as Osteopontin (SPP1). We hypothesize that these genes have a role in the biology of metastatic disease and that they represent potential therapeutic targets for prostate cancer.
Gene expression profiles of prostate cancer reveal involvement of multiple molecular pathways in the metastatic process.
Age, Specimen part, Race
View SamplesDuring S-phase of the cell cycle production of the core histone proteins is precisely balanced with DNA replication. Metazoan mRNAs encoding replication dependent (RD) histones lack polyA tail normally formed by 3' end cleavage and coupled polyadenylation of the pre-mRNA. Instead, they undergoes to endonucleolytic cleavage on the 3' side of an RNA hairpin (stem loop) producing mRNA with a 3´-stem loop (SL), which is exported from the nucleus for use in translation. The same endonuclease that is involved in normal protein-coding pre-mRNA cleavage, i.e. cleavage and poyladenylation specificity factor 73 (CPSF73), is proposed to catalyse RD pre-histone mRNA cleavage. Additional factors specific to RD pre-histone mRNA processing, including stem loop binding protein (SLBP) and the U7 small nuclear ribonucleoprotein (U7snRNP) that binds to a histone downstream element (HDE) are thought to be involved in CPSF73 targeting to RD pre-histone mRNA. We report that a different histone specific endonuclease (HSE), which like CPSF73 is a metallo ß lactamase (MBL) fold protein, is specific for RD pre-histone mRNA cleavage10,11. Crystallographic and biochemical studies reveal HSE has a di-zinc ion containing active site related to that of CPSF73, but which has distinct overall fold. Notably HSE depletion from cells leads to the production of unprocessed RD pre-histone mRNA due to inefficient 3' end processing. The consequent depletion of core histone proteins correlates with a cell cycle defect due to a delay in entering/progressing through S-phase. HSE thus may represent a new type of S-phase specific cancer target. Overall design: Examination of chromatin mRNA profiles in HeLa cells after depletion of HSE or CPSF73 by siRNA treatment.
Biosynthesis of histone messenger RNA employs a specific 3' end endonuclease.
Specimen part, Subject
View SamplesThe incidence of prostate cancer is frequent, occurring in almost one-third of men older than 45 years. Only a fraction of the cases reach the stages displaying clinical significance. Despite the advances in our understanding of prostate carcinogenesis and disease progression, our knowledge of this disease is still fragmented. Identification of the genes and patterns of gene expression will provide a more cohesive picture of prostate cancer biology. PATIENTS AND METHODS: In this study, we performed a comprehensive gene expression analysis on 152 human samples including prostate cancer tissues, prostate tissues adjacent to tumor, and organ donor prostate tissues, obtained from men of various ages, using the Affymetrix (Santa Clara, CA) U95a, U95b, and U95c chip sets (37,777 genes and expression sequence tags). RESULTS: Our results confirm an alteration of gene expression in prostate cancer when comparing with nontumor adjacent prostate tissues. However, our study also indicates that the gene expression pattern in tissues adjacent to cancer is so substantially altered that it resembles a cancer field effect. CONCLUSION: We also found that gene expression patterns can be used to predict the aggressiveness of prostate cancer using a novel model.
Gene expression alterations in prostate cancer predicting tumor aggression and preceding development of malignancy.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesNutritional and genetic risk factors for intestinal tumors are additive on mouse tumor phenotypes, demonstrating that diet and genetic factors impact risk by distinct combinatorial mechanisms. We analyzed expression profiles of small intestine crypts and villi from mice with nutritional and genetic risk factors. The results advanced our understanding of the mechanistic roles played by major risk factors in the pathogenesis of intestinal tumors.
Paneth cell marker expression in intestinal villi and colon crypts characterizes dietary induced risk for mouse sporadic intestinal cancer.
Age, Specimen part
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