Project description:We report RNA polymerase II occupancy profiles across the genome of S.cerevisiae strains deleted or depleted for the protein Xrn1. This allowed investigating the role of Xrn1 in RNA polymerase II transcription.
Project description:The goal of the project was to study the transcription rates and mRNA levels, genome-wide, in several mutants in Xrn1 defetive in nuclear import. We used Genomic Run-On (GRO) experiment in wild type and xrn1 mutant strains.
Project description:To investigate changes in the elongating form of RNA Polymerase II across different conditions, we peformed ChIP-seq using antibody against the Ser5P RNAPII of pTEFb in K562 cells at 4 days after modified allele expression We then performed coverage plot analyses using data obtained from ChIP-seq from IP and Input fractions to investigate Ser5P RNAPII distribution changes
Project description:To investigate changes in the elongating form of RNA Polymerase II across different conditions, we peformed ChIP-seq using antibody against the Ser2P RNAPII of pTEFb in K562 cells at 4 days after modified allele expression We then performed coverage plot analyses using data obtained from ChIP-seq from IP and Input fractions to investigate Ser2P RNAPII distribution changes
Project description:Alterations in global mRNA decay can broadly impact multiple upstream and downstream stages of gene expression. For example, accelerated cytoplasmic mRNA degradation can trigger a reduction in mammalian RNA polymerase II (RNAPII) transcription, although signals that connect these seemingly distal processes remain largely unknown. Here, we used tandem mass tag labeling with mass spectrometry to chart how changes in Xrn1-dependent mRNA degradation impact nuclear-cytoplasmic protein distribution in human cells. Notably, accelerating mRNA decay through expression of a gammaherpesviral endonuclease known to coordinate with Xrn1 drove nuclear relocalization of many RNA binding proteins. Particularly enriched in the relocalized subset were factors linked to the poly(A) tail. Conversely, cells lacking Xrn1 exhibited changes in the localization and/or abundance of numerous factors linked to mRNA turnover. Based on these data, we uncovered a new role for cytoplasmic poly(A) binding protein in repressing RNAPII transcription upon its mRNA decay-induced translocation to the nucleus.
Project description:mRNA homeostasis is favored by crosstalk between transcription and degradation machineries. Both the Ccr4-Not and the Xrn1-decaysome complexes have been described to influence transcription. While Ccr4-Not has been shown to directly stimulate transcription elongation, the information available on how Xrn1 influences transcription is scarce and contradictory. In this study we have addressed this issue by mapping RNA polymerase II (RNA pol II) at high resolution, using CRAC and BioGRO-seq techniques in Saccharomyces cerevisiae. We found significant effects of Xrn1 perturbation on RNA pol II profiles across the genome. RNA pol II profiles at 5’ exhibited significant reductions in slope that were compatible with decreased elongation rates. This phenomenon was also observed soon after the nuclear pool of Xrn1 was depleted. Nucleosome mapping confirmed drastically altered chromatin dynamics. We also found an accumulation of arrested RNA pol II at the 3’ end, immediately upstream of polyadenylation sites of most genes, with particular incidence in those functionally related to regulatory processes. Lack of Xrn1 provoked alterations in RNA pol II CTD phosphorylation and increased recruitment of 3’ pre-mRNA processing factors. However, accumulation of RNA pol II at 3’ ends was rather related to the nucleosomal configuration of those regions.
Project description:mRNA homeostasis is favored by crosstalk between transcription and degradation machineries. Both the Ccr4-Not and the Xrn1-decaysome complexes have been described to influence transcription. While Ccr4-Not has been shown to directly stimulate transcription elongation, the information available on how Xrn1 influences transcription is scarce and contradictory. In this study we have addressed this issue by mapping RNA polymerase II (RNA pol II) at high resolution, using CRAC and BioGRO-seq techniques in Saccharomyces cerevisiae. We found significant effects of Xrn1 perturbation on RNA pol II profiles across the genome. RNA pol II profiles at 5’ exhibited significant reductions in slope that were compatible with decreased elongation rates. This phenomenon was also observed soon after the nuclear pool of Xrn1 was depleted. Nucleosome mapping confirmed drastically altered chromatin dynamics. We also found an accumulation of arrested RNA pol II at the 3’ end, immediately upstream of polyadenylation sites of most genes, with particular incidence in those functionally related to regulatory processes. Lack of Xrn1 provoked alterations in RNA pol II CTD phosphorylation and increased recruitment of 3’ pre-mRNA processing factors. However, accumulation of RNA pol II at 3’ ends was rather related to the nucleosomal configuration of those regions.
Project description:GRO (Genomic run-on) experiments with different mutants that affect to the accumulation of non active RNA pol II along the yeast genome. Keywords: Genomic run-on GRO
