Suppressors of PHO regulon hyper-repression by Pol2 CTD Thr4 mutation implicate inositol 1-pyrophosphates as agonists of precocious lncRNA transcription termination
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ABSTRACT:
ORGANISM(S): Schizosaccharomyces pombe
PROVIDER: GSE155609 | GEO | 2020/09/03
REPOSITORIES: GEO
Similar Datasets
Project description:Fission yeast phosphate homeostasis genes are repressed in phosphate-rich medium by transcription of upstream lncRNAs that interferes with activation of the flanking mRNA promoters. lncRNA control of PHO gene expression is influenced by the Thr4 phospho-site in the RNA polymerase II CTD and the 3' processing/termination factors CPF and Rhn1, mutations of which result in hyper-repression of the PHO regulon. Here, we performed a forward genetic screen for mutations that de-repress Pho1 acid phosphatase expression in CTD-T4A cells. Sequencing of 18 independent STF (Suppressor of Threonine Four) isolates revealed, in every case, a mutation in the C-terminal pyrophosphatase domain of Asp1, a bifunctional inositol pyrophosphate (IPP) kinase/pyrophosphatase that interconverts 5-IP7 and 1,5-IP8. Focused characterization of two STF strains identified 51 coding genes coordinately upregulated vis-à-vis the parental T4A strain, including all three PHO regulon genes (pho1, pho84, tgp1). Whereas these STF alleles-asp1-386(Stop) and asp1-493(Stop)-were lethal in a wild-type CTD background, they were viable in combination with mutations in CPF and Rhn1, in which context Pho1 was also de-repressed. Our findings implicate Asp1 pyrophosphatase in constraining 1,5-IP8 or 1-IP7 synthesis by Asp1 kinase, without which 1-IPPs can accumulate to toxic levels that elicit precocious termination by CPF/Rhn1.
| S-EPMC7641756 | biostudies-literature
Project description:Suppressors of PHO regulon hyper-repression by Pol2 CTD Thr4 mutation implicate inositol 1-pyrophosphates as agonists of precocious lncRNA transcription termination
| PRJNA650467 | ENA
Project description:The carboxy-terminal domain (CTD) of RNA polymerase II (Pol II) consists of heptad repeats with the consensus motif Y1-S2-P3-T4-S5-P6-S7. Dynamic phosphorylation of the CTD coordinates Pol II progression through the transcription cycle. Monoclonal antibodies have been used to study in vivo the potentially phosphorylated CTD amino acids (Y1, S2, T4, S5 and S7). However, the epitopes detected by antibodies can be masked by proteins or modifications at neighbouring sites. Therefore, the effectiveness of antibodies in western blot or ChIP analysis reflects the number of accessible CTD phosphorylation marks, but not the total number of phosphorylations. Most importantly, CTD phospho-specific antibodies do not provide any heptad - (location) specific information of CTD phosphorylation. Due to these limitations, the principles and patterns of CTD phosphorylation remained elusive. Here, we use genetic and mass spectrometric approaches to directly detect and map phosphosites along the entire CTD. We confirm phosphorylation of CTD residues Y1, S2, T4, S5 and S7 in mammalian and yeast cells. Although specific phosphorylation signatures dominate, adjacent CTD repeats can be differently phosphorylated, leading to a high variation of coexisting phosphosites in mono- and di-heptad CTD repeats. Inhibition of CDK9 kinase specifically reduces S2 phosphorylation levels within the CTD.
2016-01-25 | PXD003159 | Pride
Project description:The carboxy-terminal domain (CTD) of the largest subunit of RNA Polymerase II (RNAPII) consists of multiple tandem repeats of the heptapeptide consensus Y1-S2-P3-T4-S5-P6-S7. RNAPII CTD is intrinsically disordered and has been shown to promote liquid-liquid phase-separation (LLPS) of RNAPII in vivo. However, understanding the precise role of the conserved heptad residues in LLPS has been hampered by the lack of direct characterization of the biochemical properties of the CTD. Here, we generated a systematic array of RNAPII CTD variants to unravel the sequence-encoded molecular grammar underlying LLPS of the human CTD.
2024-09-19 | PXD049700 | Pride
Project description:Transcription termination in Saccharomyces cerevisiae can be performed by at least two distinct pathways and is directed by the phosphorylation status of the carboxy-terminal domain (CTD) of RNA polymerase II (Pol II). Late termination of mRNAs is performed by the CPF/CF complex and requires CTD-Ser2 phosphorylation. Early termination of shorter cryptic unstable transcripts (CUTs) and small nucleolar RNAs (snoRNAs) is preformed by the Nrd1 complex, and requires CTD-Ser5 phosphorylation. In this study, mutants of the different termination pathways were compared by genome-wide expression analysis. Surprisingly, the expression changes observed upon loss of the CTD-Ser2 kinase Ctk1 are more similar to loss of a subunit of the Ser5P binding Nrd1-complex, than to loss of Ser2P binding factors. Tiling array analysis of ctk1Δ reveals readthrough at several hundred sites, including snoRNAs, as reported previously, but also many cryptic unstable transcripts, stable untranslated transcripts (SUTs) and other transcripts. Surprisingly, neither loss of CTK1 nor a Pol II CTD-Ser2 substitution mutant results in a global defect in termination of mRNAs, indicating that Ser2P is not essential for proper termination of most mRNAs. At snoRNA, Nrd1 location is shifted downstream in ctk1∆, indicating defective release rather than recruitment of Nrd1. Weakening the interaction between Nrd1 and Pol II rescues the readthrough in ctk1∆, likely by facilitating Nrd1 release. The termination defect is kinase activity dependent, but cannot be completely explained by loss of CTD-Ser2 phosphorylation , a major substrate of Ctk1, suggesting the involvement of an additional substrate. Mutant alleles of the elongation factor Spt5 rescue ctk1∆-dependent readthrough, indicating a role for Spt5 in this process, perhaps as a substrate of Ctk1. The results show that Ctk1 is more intimately involved in termination of small non-coding RNAs than was previously assumed and lead to a model in which Ctk1 influences Spt5 activity to achieve this.
2014-04-22 | GSE40254 | GEO
Project description:This RNA-Seq analysis compares gene expression of the RNA polymerase II CTD-mutants contrasting to the WT RNA polymerase II CTD (with isogenic 3' selection marker) in the fission yeast S. pombe
2021-02-25 | GSE160852 | GEO
Project description:The carboxyl-terminal domain (CTD) of the largest subunit of RNA polymerase II (Pol II) orchestrates dynamic recruitment of specific cellular machines during different stages of transcription. Signature phosphorylation patterns of Y1S2P3T4S5P6S7 heptapeptide repeats of the CTD engage specific “readers.” While phospho-Ser5 and phospho-Ser2 marks are ubiquitous, phospho-Thr4 is reported to only impact specific genes. Here, we investigate the RNA expression profile in WT and CTD-mutant strains of S. cerevisiae.
2017-05-02 | GSE95417 | GEO
Project description:The C-terminal domain (CTD) of RNA polymerase II (RNAPII) is composed of heptapeptide repeats, which play a key regulatory role in gene expression. Using genetic interaction and mRNA expression analysis we found that truncating the CTD resulted in distinct changes to cellular function. Truncating the CTD altered RNAPII occupancy to not only cause decreases, but also increases in mRNA levels. The latter were largely mediated by promoter elements, and in part were linked to the transcription factor Rpn4. The mediator subunit Cdk8 was enriched at promoters of these genes, and its removal not only restored normal mRNA and RNAPII occupancy levels, but also reduced the abnormally high cellular amounts of Rpn4. This suggested a positive role of Cdk8 in relationship to RNAPII, which contrasted with the negative role at the activated INO1 gene. Here, loss of CDK8 suppressed the reduced mRNA expression and RNAPII occupancy levels of CTD truncation mutants.
2013-09-13 | GSE43120 | GEO
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.
2012-06-29 | E-MTAB-1060 | biostudies-arrayexpress