Project description:We used ChIP-seq to map binding of the CRISPR surveillance complex, Cascade, in a Salmonella enterica serovar Typhimurium strain lacking the gene encoding the endonuclease Cas3. We performed ChIP-seq in strains with wild-type and mutant sequences upstream of the two CRISPR arrays, and in strains with wild-type and mutant nusE genes to determine the impact of Nus factor antitermination on CRISPR array function.
Project description:We report a function of human mRNA decapping factors in control of transcription by RNA polymerase II. Decapping proteins Edc3, Dcp1a and Dcp2 and the termination factor TTF2 co-immunoprecipitate with Xrn2, the nuclear 5'-3' exonuclease torpedo that facilitates transcription termination at the 3' ends of genes. Dcp1a, Xrn2 and TTF2 localize near transcription start sites (TSSs) by ChIP-Seq. At genes with 5' peaks of paused pol II, knockdown of decapping or termination factors, Xrn2 and TTF2, shifted polymerase away from the TSS toward upstream and downstream distal positions. This re-distribution of pol II is similar in magnitude to that caused by depletion of the elongation factor Spt5. We propose that coupled decapping of nascent transcripts and premature termination by the torpedo mechanism is a widespread mechanism that limits bidirectional pol II elongation. Regulated co-transcriptional decapping near promoter-proximal pause sites followed by premature termination could control productive pol II elongation. RNA pol II (GSE30895: GSM766171), Xrn2, TTF2 and Dcp1a were localized by ChIP-Seq in HeLa cells. RNA pol II was localized in control HEK293 cells and cells infected with lentiviruses expressing a scrambled control shRNA (scr), and shRNAs targeting the following proteins: Xrn2, TTF2, Xrn2+TTF2, Edc3, Dcp1a, and Dcp2.
Project description:We report a function of human mRNA decapping factors in control of transcription by RNA polymerase II. Decapping proteins Edc3, Dcp1a and Dcp2 and the termination factor TTF2 co-immunoprecipitate with Xrn2, the nuclear 5'-3' exonuclease torpedo that facilitates transcription termination at the 3' ends of genes. Dcp1a, Xrn2 and TTF2 localize near transcription start sites (TSSs) by ChIP-Seq. At genes with 5' peaks of paused pol II, knockdown of decapping or termination factors, Xrn2 and TTF2, shifted polymerase away from the TSS toward upstream and downstream distal positions. This re-distribution of pol II is similar in magnitude to that caused by depletion of the elongation factor Spt5. We propose that coupled decapping of nascent transcripts and premature termination by the torpedo mechanism is a widespread mechanism that limits bidirectional pol II elongation. Regulated co-transcriptional decapping near promoter-proximal pause sites followed by premature termination could control productive pol II elongation.
Project description:Co-transcriptional RNA processing and surveillance factors mediate heterochromatin formation in fission yeast. In addition to RNAi, RNA elimination machinery including MTREC (Mtl1-Red1 core) and the exosome are involved in facultative heterochromatin assembly, however, the exact mechanisms remain unclear. Here we show that RNA elimination factors cooperate with the conserved exoribonuclease Dhp1/Rat1/Xrn2, which couples pre-mRNA 3â-end processing to transcription termination, to promote premature termination and facultative heterochromatin formation at meiotic genes. Dhp1 also affects termination of transcripts at genes that are targets of RNAi-mediated heterochromatin assembly. Moreover, Dhp1 facilitates constitutive heterochromatin formation and silencing at centromeric and mating-type loci. Remarkably, we find that Dhp1 interacts with the Clr4/Suv39h methyltransferase complex and acts directly to nucleate heterochromatin. Our results uncover a novel role for 3â-end processing and termination machinery in gene silencing through premature termination and suggest that non-canonical termination by Dhp1 and RNA elimination factors is linked to heterochromatin assembly. These findings have important implications for understanding mechanisms of gene silencing in higher eukaryotes. Sequencing and analysis of small RNA in two S. pombe mutants
Project description:The pervasive nature of RNA polymerase II (Pol II) transcription requires efficient termination. A key player in this process is the cleavage and polyadenylation (CPA) factor PCF11, which directly binds to the Pol II C-terminal domain and dismantles elongating Pol II from DNA in vitro. We demonstrate that PCF11-mediated termination is essential for vertebrate development. A range of genomic analyses, including: mNET-seq, 3’ mRNA-seq, chromatin RNA-seq and ChIP-seq, reveals that PCF11 enhances transcription termination and stimulates early polyadenylation genome-wide. PCF11 binds preferentially between closely spaced genes, where it prevents transcriptional interference and downstream gene silencing. Notably, PCF11 is sub-stoichiometric to the CPA complex. Low levels of PCF11 are maintained by an auto-regulatory mechanism involving premature termination of its own transcript, and are important for normal development. Both in human cell culture and during zebrafish development, PCF11 selectively attenuates the expression of other transcriptional regulators by premature CPA and termination.
Project description:The pervasive nature of RNA polymerase II (Pol II) transcription requires efficient termination. A key player in this process is the cleavage and polyadenylation (CPA) factor PCF11, which directly binds to the Pol II C-terminal domain and dismantles elongating Pol II from DNA in vitro. We demonstrate that PCF11-mediated termination is essential for vertebrate development. A range of genomic analyses, including: mNET-seq, 3’ mRNA-seq, chromatin RNA-seq and ChIP-seq, reveals that PCF11 enhances transcription termination and stimulates early polyadenylation genome-wide. PCF11 binds preferentially between closely spaced genes, where it prevents transcriptional interference and downstream gene silencing. Notably, PCF11 is sub-stoichiometric to the CPA complex. Low levels of PCF11 are maintained by an auto-regulatory mechanism involving premature termination of its own transcript, and are important for normal development. Both in human cell culture and during zebrafish development, PCF11 selectively attenuates the expression of other transcriptional regulators by premature CPA and termination.
Project description:The pervasive nature of RNA polymerase II (Pol II) transcription requires efficient termination. A key player in this process is the cleavage and polyadenylation (CPA) factor PCF11, which directly binds to the Pol II C-terminal domain and dismantles elongating Pol II from DNA in vitro. We demonstrate that PCF11-mediated termination is essential for vertebrate development. A range of genomic analyses, including: mNET-seq, 3’ mRNA-seq, chromatin RNA-seq and ChIP-seq, reveals that PCF11 enhances transcription termination and stimulates early polyadenylation genome-wide. PCF11 binds preferentially between closely spaced genes, where it prevents transcriptional interference and downstream gene silencing. Notably, PCF11 is sub-stoichiometric to the CPA complex. Low levels of PCF11 are maintained by an auto-regulatory mechanism involving premature termination of its own transcript, and are important for normal development. Both in human cell culture and during zebrafish development, PCF11 selectively attenuates the expression of other transcriptional regulators by premature CPA and termination.
Project description:The pervasive nature of RNA polymerase II (Pol II) transcription requires efficient termination. A key player in this process is the cleavage and polyadenylation (CPA) factor PCF11, which directly binds to the Pol II C-terminal domain and dismantles elongating Pol II from DNA in vitro. We demonstrate that PCF11-mediated termination is essential for vertebrate development. A range of genomic analyses, including: mNET-seq, 3’ mRNA-seq, chromatin RNA-seq and ChIP-seq, reveals that PCF11 enhances transcription termination and stimulates early polyadenylation genome-wide. PCF11 binds preferentially between closely spaced genes, where it prevents transcriptional interference and downstream gene silencing. Notably, PCF11 is sub-stoichiometric to the CPA complex. Low levels of PCF11 are maintained by an auto-regulatory mechanism involving premature termination of its own transcript, and are important for normal development. Both in human cell culture and during zebrafish development, PCF11 selectively attenuates the expression of other transcriptional regulators by premature CPA and termination.
Project description:The pervasive nature of RNA polymerase II (Pol II) transcription requires efficient termination. A key player in this process is the cleavage and polyadenylation (CPA) factor PCF11, which directly binds to the Pol II C-terminal domain and dismantles elongating Pol II from DNA in vitro. We demonstrate that PCF11-mediated termination is essential for vertebrate development. A range of genomic analyses, including: mNET-seq, 3’ mRNA-seq, chromatin RNA-seq and ChIP-seq, reveals that PCF11 enhances transcription termination and stimulates early polyadenylation genome-wide. PCF11 binds preferentially between closely spaced genes, where it prevents transcriptional interference and downstream gene silencing. Notably, PCF11 is sub-stoichiometric to the CPA complex. Low levels of PCF11 are maintained by an auto-regulatory mechanism involving premature termination of its own transcript, and are important for normal development. Both in human cell culture and during zebrafish development, PCF11 selectively attenuates the expression of other transcriptional regulators by premature CPA and termination.