RNA polymerase II stalling at pre-mRNA splice sites is enforced by ubiquitination of the catalytic subunit
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE94944 | GEO | 2017/10/22
SECONDARY ACCESSION(S): PRJNA374881
REPOSITORIES: GEO
Similar Datasets
Project description:Numerous links exist between co-transcriptional RNA processing and the transcribing RNAPII. In particular, pre-mRNA splicing was reported to be associated with slowed RNAPII elongation. Here, we identify a site of ubiquitination (K1246) in the catalytic subunit of RNAPII close to the DNA entry path. Ubiquitination was increased in the absence of the Bre5-Ubp3 ubiquitin protease complex. Bre5 binds RNA in vivo, with a preference for exon 2 regions of intron-containing pre-mRNAs and poly(A) proximal sites. Ubiquitinated RNAPII showed similar enrichment. The absence of Bre5 led to impaired splicing and defects in RNAPII elongation in vivo on a splicing reporter construct. Strains expressing RNAPII with a K1246R mutation showed reduced co-transcriptional splicing. We propose that ubiquinitation of RNAPII is induced by RNA processing events and linked to transcriptional pausing, which is released by Bre5-Ubp3 associated with the nascent transcript.
| S-EPMC5673307 | biostudies-literature
Project description:Genome wide screens identified negative genetic interactions between several cofactors of the exosome nuclease complex and the Bre5-Ubp3 ubiquitin protease complex. RNA-binding was shown for Bre5 with enrichment for sites over exon 2 of spliced pre-mRNAs and close to poly(A) sites. An inducible splicing-reporter showed a requirement for Bre5 in efficient in vivo splicing and for normal RNAPII elongation, specifically on splicing-competent genes. A Bre5-Ubp3 sensitive site of RNAPII ubiquitination was mapped at Lys1246 at the entrance to the active site of the large subunit. Ubiquitinated RNAPII was depleted at the TSS but enriched at the 5’ end of exon 2 and upstream of poly(A) sites, similar to Bre5. Mutation of Lys1246 reduced RNAPII occupancy upstream of the poly(A) site, consistent with reduced pausing at a potential surveillance site, but increased RNAPII residence downstream of the poly(A) site. Strains expressing RNAPII with the Lys1246 mutation showed increased levels of unspliced but poly(A)+ RNA, indicating reduced cotranscriptional splicing efficiency. We propose that ubiquinitation of RNAPII is induced by RNA processing events and linked to transcriptional pausing, which is released by Bre5-Ubp3 associated with the nascent transcript.
2017-10-22 | GSE94941 | GEO
Project description:Genome wide screens identified negative genetic interactions between several cofactors of the exosome nuclease complex and the Bre5-Ubp3 ubiquitin protease complex. RNA-binding was shown for Bre5 with enrichment for sites over exon 2 of spliced pre-mRNAs and close to poly(A) sites. An inducible splicing-reporter showed a requirement for Bre5 in efficient in vivo splicing and for normal RNAPII elongation, specifically on splicing-competent genes. A Bre5-Ubp3 sensitive site of RNAPII ubiquitination was mapped at Lys1246 at the entrance to the active site of the large subunit. Ubiquitinated RNAPII was depleted at the TSS but enriched at the 5’ end of exon 2 and upstream of poly(A) sites, similar to Bre5. Mutation of Lys1246 reduced RNAPII occupancy upstream of the poly(A) site, consistent with reduced pausing at a potential surveillance site, but increased RNAPII residence downstream of the poly(A) site. Strains expressing RNAPII with the Lys1246 mutation showed increased levels of unspliced but poly(A)+ RNA, indicating reduced cotranscriptional splicing efficiency. We propose that ubiquinitation of RNAPII is induced by RNA processing events and linked to transcriptional pausing, which is released by Bre5-Ubp3 associated with the nascent transcript.
2017-10-22 | GSE94942 | GEO
Project description:RNA polymerase II stalling at pre-mRNA splice sites is enforced by ubiquitination of the catalytic subunit
| PRJNA374881 | ENA
Project description:Activation-induced cytidine deaminase (AID) initiates antibody gene diversification by creating U:G mismatches. However, AID is not specific for antibody genes; Off-target lesions can activate oncogenes or cause chromosome translocations. Despite its importance in these transactions little is known about how AID finds its targets. We performed an shRNA screen to identify factors required for class switch recombination (CSR) of antibody loci. We found that Spt5, a factor associated with stalled RNA polymerase II (Pol II) and single stranded DNA (ssDNA), is required for CSR. Spt5 interacts with AID, it facilitates association between AID and Pol II, and AID recruitment to its Ig and non-Ig targets. ChIP-seq experiments reveal that Spt5 colocalizes with AID and stalled Pol II. Further, Spt5 accumulation at sites of Pol II stalling is predictive of AID-induced mutation. We propose that AID is targeted to sites of Pol II stalling in part via its association with Spt5.
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Project description:Several anticancer agents that form DNA adducts in the minor groove interfere with DNA replication and transcription to induce apoptosis. Therapeutic resistance can occur, however, when cells are proficient in the removal of drug-induced damage. Acylfulvenes are a class of experimental anticancer agents with a unique repair profile suggesting their capacity to stall RNA polymerase (Pol) II and trigger transcription-coupled nucleotide excision repair. Here we show how different forms of DNA alkylation impair transcription by RNA Pol II in cells and with the isolated enzyme and unravel a mode of RNA Pol II stalling that is due to alkylation of DNA in the minor groove. We incorporated a model for acylfulvene adducts, the stable 3-deaza-3-methoxynaphtylethyl-adenosine analog (3d-Napht-A), and smaller 3-deaza-adenosine analogs, into DNA oligonucleotides to assess RNA Pol II transcription elongation in vitro. RNA Pol II was strongly blocked by a 3d-Napht-A analog but bypassed smaller analogs. Crystal structure analysis revealed that a DNA base containing 3d-Napht-A can occupy the +1 templating position and impair closing of the trigger loop in the Pol II active center and polymerase translocation into the next template position. These results show how RNA Pol II copes with minor-groove DNA alkylation and establishes a mechanism for drug resistance.
| S-EPMC5699039 | biostudies-literature
Project description:Histone H2B monoubiquitylation plays an important role in RNA polymerase II (RNAPII) elongation. Whether this modification responds to RNAPII stalling is not yet known. We report that both yeast and human cells undergo a rapid and significant H2B deubiquitylation after exposure to UV irradiation. This deubiquitylation occurs concurrently with UV-induced transcription arrest and is significantly reduced in a DNA damage-bypassing RNAPII yeast mutant. Consistent with these results, yeast deubiquitylases Ubp8 and Ubp10 are associated with the RNAPII complex. Moreover, simultaneous deletion of Ubp8 and Ubp10 leads to a lack of H2B deubiquitylation after UV exposure. Consequently, nucleotide excision repair at an actively transcribed gene locus is decreased, whereas UV-induced RNAPII degradation is increased in ubp8?ubp10? mutant cells. These results indicate that eukaryotic cells respond to RNAPII arrest by deubiquitylating H2B to coordinate DNA repair and RNAPII degradation.
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Project description:REV3L, the catalytic subunit of DNA polymerase ζ (Pol ζ), is indispensable for translesion DNA synthesis, which protects cells from deleterious DNA lesions resulting from various intrinsic and environmental sources. However, REV3L lacks a proofreading exonuclease activity and consequently bypasses DNA lesions at the expense of increased mutations, which poses a severe threat to genome stability. Here we report a site-specific proteolytic event of human REV3L. We show that REV3L is cleaved by a threonine aspartase, Taspase1 (TASP1), to generate an N-terminal 70-kDa fragment (N70) and a polypeptide carrying the C-terminal polymerase catalytic domain in human cells. Strikingly, such a post-translational cleavage event plays a vital role in controlling REV3L stability by preventing ubiquitination and proteasome-mediated degradation of REV3L. Indicative of the biological importance of the above REV3L post-translational processing, cellular responses to UV and cisplatin-induced DNA lesions are markedly impaired in human HCT116 cell derivatives bearing defined point mutations in the endogenous REV3L gene that compromise REV3L cleavage. These findings establish a new paradigm in modulating the abundance of REV3L through site-specific proteolysis in human cells.
| S-EPMC7144948 | biostudies-literature
Project description:Somatic hypermutation (SHM) drives the genetic diversity of Ig genes in activated B cells and supports the generation of Abs with increased affinity for Ag. SHM is targeted to Ig genes by their enhancers (diversification activators [DIVACs]), but how the enhancers mediate this activity is unknown. We show using chicken DT40 B cells that highly active DIVACs increase the phosphorylation of RNA polymerase II (Pol II) and Pol II occupancy in the mutating gene with little or no accompanying increase in elongation-competent Pol II or production of full-length transcripts, indicating accumulation of stalled Pol II. DIVAC has similar effect also in human Ramos Burkitt lymphoma cells. The DIVAC-induced stalling is weakly associated with an increase in the detection of ssDNA bubbles in the mutating target gene. We did not find evidence for antisense transcription, or that DIVAC functions by altering levels of H3K27ac or the histone variant H3.3 in the mutating gene. These findings argue for a connection between Pol II stalling and cis-acting targeting elements in the context of SHM and thus define a mechanistic basis for locus-specific targeting of SHM in the genome. Our results suggest that DIVAC elements render the target gene a suitable platform for AID-mediated mutation without a requirement for increasing transcriptional output.
| S-EPMC8702490 | biostudies-literature
Project description:DNA cytosine methylation is an important epigenetic mechanism that is involved in transcriptional silencing of developmental genes. Several molecular pathways have been described that interfere with Pol II initiation, but at individual genes the molecular mechanism of repression remains uncertain. Here, we study the molecular mechanism of transcriptional regulation at Hox genes in dependence of the epigenetic regulator Lsh that controls CpG methylation at selected Hox genes. Wild type cells show a nucleosomal deprived region around the transcriptional start site at methylated Hox genes and mediate gene silencing via Pol II stalling. Hypomethylation in Lsh-/- cells is associated with efficient transcriptional elongation and splicing, in part mediated by the chromodomain protein Chd1. Dynamic modulation of DNA methylation in Lsh-/- and wild type cells demonstrates that catalytically active DNA methyltransferase activity is required for Pol II stalling. Taken together, the data suggests that DNA methylation can be compatible with Pol II binding at selected genes and Pol II stalling can act as alternate mechanism to explain transcriptional silencing associated with DNA methylation.
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