Project description:Purpose: In this study, we show that DNA damage-activated AKT phosphorylates threonine 45 of core histone H3 (H3-T45) Result: By genome-wide chromatin immunoprecipitation sequencing (ChIP-seq) analysis, H3-T45 phosphorylation was distributed throughout DNA damage-responsive gene loci, particularly immediately after the transcription termination site Conclusion: AKT-mediated phosphorylation of H3-T45 regulates the processing of the 3′ end of DNA damage-activated genes to facilitate transcriptional termination MCF10A cells were ChIPed with anti-phosphorylated H3-T45, anti-phosphorylated RNA Pol II-S2 and S5, and anti-H3-K36me3.
Project description:Purpose: In this study, we show that DNA damage-activated AKT phosphorylates threonine 45 of core histone H3 (H3-T45) Result: By genome-wide chromatin immunoprecipitation sequencing (ChIP-seq) analysis, H3-T45 phosphorylation was distributed throughout DNA damage-responsive gene loci, particularly immediately after the transcription termination site Conclusion: AKT-mediated phosphorylation of H3-T45 regulates the processing of the 3′ end of DNA damage-activated genes to facilitate transcriptional termination
Project description:We report that TAF1 phosphorylates p53 at Thr55 on the p21 promoter and this phosphorylation leads to dissociation of p53 from the promoter. Indeed, ChIP-Seq analysis reveals p53 undergoes promoter dissociation at a global level after response to DNA damage, underscoring general nature of the regulation. UVC treatment at the time points indicated was used to access p53 transcription factor signal induction and termination.
Project description:Drosophila Haspin kinase phosphorylates Histone H3 at threonine 3 at centromeric heterochromatin and either lamin- or polycomb-enriched euchromatic regions, being required for nuclear organization of interphase cells and polycomb-dependent gene silencing.
Project description:Termination of RNA polymerase II (Pol II) transcription is a key step, that is important for 3’end formation of functional mRNA, mRNA release and Pol II recycling. Even so, this underlying termination mechanism is not yet understood. Here, we demonstrate that the conserved and essential termination factor Seb1 interacts with Pol II near the end of the RNA exit channel and the Rpb4/7 stalk. Furthermore, the Seb1 interaction surface with Pol II largely overlaps with that of the elongation factor Spt5. Notably, Seb1 co-transcriptional recruitment is dependent on Spt5 de-phosphorylation by the conserved PP1 phosphatase Dis2, which also de-phosphorylates threonine 4 within the Pol II heptad repeated C-terminal domain. We propose that Dis2 orchestrates the transition from elongation to termination phase during the transcription cycle by mediating elongation to termination factor exchange and de-phosphorylation of Pol II C-terminal domain.
Project description:We demonstrate that the Cdc7/Dbf4-dependent histone modification, H3 threonine 45 phosphorylation (H3T45p), is specifically enriched at origins of replication, and highly transcribed genes involved in protein synthesis and glycolysis. Furthermore, we show that H3T45p also mediates polymerase recruitment and expression of these genes.
Project description:Base J and H3.V promote RNA Polymerase (RNAP) II termination within polycistronic gene clusters in the kinetoplastid species Trypanosoma brucei. Although base J has been shown to promote RNAP II termination in the related kinetoplastid species Leishmania major and Leishmania tarentolae, the role of H3.V was unclear. The effect of acute J loss on mRNA transcript abundance was also unknown. We find here that H3.V does not promote transcription termination in Leishmania major, but loss of H3.V does reduce J levels. The J loss in H3.V knockout cells is not enough to result in a termination defect, which we show is due to a threshold level of J that is sufficient to promote termination. Loss of J beyond that threshold results in termination defects. Further, the decreased J in H3.V knockout cells allowed greater reduction of J by dimethyloxalylglycine (DMOG), which inhibits J synthesis, compared to wild type cells treated with DMOG, and resulted in stronger defects in RNAP II termination and cell growth. By mRNA-seq we see largely upregulation of genes near the ends of gene clusters following J loss, indicating that J represses genes near termination sites. These findings reveal a conserved role of J in promoting termination prior to the end of polycistronic gene clusters in kinetoplastid parasites and suggest that the essential nature of J is related to its role in repressing genes by promoting termination. The role of base J and H3.V in promoting RNA Polymerase II transcription termination was assessed by small RNA-seq, mRNA-seq, and strand-specific RT-PCR. Wild type cells were compared to H3.V knockout cells and to WT and H3.V knockout cells treated with dimethyloxalylglycine (DMOG) to reduce base J.
Project description:Manuscript title: Modulated termination of non-coding transcription partakes in the regulation of gene expression Here we report high-resolution analyses of transcribing RNAPII in either a wild-type (WT) background or a sen1T1623E mutant, which harbours a substitution that mimics the phosphorylation at threonine 1623. Sen1 is a well-characterized transcription termination factor for RNAPII-dependent non-coding genes in budding yeast. Here we show that the T1623E phosphomimetic mutation induces moderate but widespread termination defects at target non-coding genes, strongly suggesting that phosphoryation at T1623 modulates negatively Sen1 transcription termination activity.
Project description:Compared to the initiation and elongation stages of transcription, the role of chromatin in transcription termination is poorly understood. Through a yeast genetic screen, we identified histone H3 and H4 substitutions that cause transcription to read through the terminator of a small noncoding gene. The substitutions map to the nucleosome DNA entry-exit site, a region that controls nucleosome stability and certain histone modifications. Genome-wide studies on the strongest mutants revealed evidence of transcription read-through of noncoding and coding genes and reduced nucleosome occupancy. Replacement of the native sequence downstream of a gene with a “superbinder” sequence that increases nucleosome occupancy in vivo increased termination efficiency and suppressed the effect of a DNA entry-exit site substitution at this locus. Our results highlight the importance of the DNA entry-exit site in maintaining the integrity of the transcriptome and suggest that nucleosomes can facilitate termination by serving as a barrier to RNA polymerase.
Project description:ChIP-chip was performed to identify the genomic binding locations for the termination factors Nrd1, and Rtt103, and for RNA polymerase (Pol) II phosphorylated at the tyrosine 1 and threonine 4 position of its C-terminal domain (CTD). In different phases of the transcription cycle, Pol II recruits different factors via its CTD, which consists of heptapeptide repeats with the sequence Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7. Here we show that the CTD of transcribing yeast Pol II is phosphorylated at Tyr1, and that this impairs recruitment of termination factors. Tyr1 phosphorylation levels rise downstream of the transcription start site (TSS), and decrease before the polyadenylation (pA) site. Tyr1-phosphorylated gene bodies are depleted of CTD-binding termination factors Nrd1, Pcf11, and Rtt103. Tyr1 phosphorylation blocks CTD binding by these termination factors, but stimulates binding of elongation factor Spt6. These results show that CTD modifications can not only stimulate but also block factor recruitment, and lead to an extended CTD code for transcription cycle coordination.