Project description:The C-terminal domain of RPB1 (CTD) orchestrates transcription by recruiting regulators to RNA Pol II upon phosphorylation. Recent insights highlight CTD’s pivotal role in driving condensate formation on gene loci. Yet, the molecular mechanism behind how CTD-mediated recruitment of transcriptional regulators influences condensates formation remains unclear. Our study unveils that phosphorylation reversibly dissolves phase separation induced by the unphosphorylated CTD. Phosphorylated CTD, upon specific association with transcription regulatory proteins, forms distinct condensates from unphosphorylated CTD. Function studies demonstrate CTD variants with diverse condensation properties in vitro exhibit difference in promoter binding and mRNA co-processing in cells. Notably, varying CTD lengths lead to alternative splicing outcomes impacting cellular growth, linking the evolution of CTD variation/length with the complexity of splicing from yeast to human. These findings provide compelling evidence for a model wherein post-translational modification enables the transition of functionally specialized condensates, highlighting a co-evolution link between CTD condensation and splicing.
Project description:The C-terminal domain of RPB1 (CTD) orchestrates transcription by recruiting regulators to RNA Pol II upon phosphorylation. Recent insights highlight CTD’s pivotal role in driving condensate formation on gene loci. Yet, the molecular mechanism behind how CTD-mediated recruitment of transcriptional regulators influences condensates formation remains unclear. Our study unveils that phosphorylation reversibly dissolves phase separation induced by the unphosphorylated CTD. Phosphorylated CTD, upon specific association with transcription regulatory proteins, forms distinct condensates from unphosphorylated CTD. Function studies demonstrate CTD variants with diverse condensation properties in vitro exhibit difference in promoter binding and mRNA co-processing in cells. Notably, varying CTD lengths lead to alternative splicing outcomes impacting cellular growth, linking the evolution of CTD variation/length with the complexity of splicing from yeast to human. These findings provide compelling evidence for a model wherein post-translational modification enables the transition of functionally specialized condensates, highlighting a co-evolution link between CTD condensation and splicing.
Project description:The carboxy-terminal domain of RPB1 subunit of RNA Polymerase II (CTD) plays an essential function in the regulation of gene expression and the coordination of co-transcriptional processes. CTD consists of hepta-amino acid repeats varying in number from 52 in humans to 26 in yeast and its length is crucial for spatial organization of transcriptional machinery in the nucleus. We found that the proximal half of the CTD is sufficient to support RNA metabolism and co-transcriptional processing in steady state conditions in human cells. Signal induced transcription, however, is severely impaired upon CTD shortening. Our data suggest that CTD length increased in evolution to allow for spatio-temporal control of gene expression patterns at least in part by facilitating enhancer function.
Project description:The modification of Ser 5 is important for the relocalization of RNAP II upon NaCl stress. The CTD14 strains harbors a plasmid expressing RPB1 with 14 wild-type CTD repeats. The 5A strain carries a plasmid expressing a chimeric RPB1 in which the CTD was composed of 5 repeats of CTD-serine 5 substituted with alanine followed by 7 wild-type-sequenced repeats.
Project description:Transctriptome profiling of CTD-14 repeats, 2A, 5A mutants responding to 0.7N NaCl for 30mins. The study shows that phosphorylation at Ser5 sites plays a role in normal induction and repression of genes upon NaCl stress. The CTD14 strains harbors a plasmid expressing RPB1 with 14 wild-type CTD repeats. 5A strains carries a plasmid expressing a chimeric RPB1 in which the CTD was composed of 5 repeats of CTD-serine 5 substituted with Ala followed by 7 wild-type-sequenced repeats. The 2A strains carrys 8 repeats of CTD-serine 2 substituted with alanine followed by 7 wild-type-sequenced repeats. Two-color fluorescence arrays reporting on mRNA abunance in strains before and after 30 min with 0.7M NaCl treatment
Project description:Transctriptome profiling of CTD-14 repeats, 2A, 5A mutants responding to 0.7N NaCl for 30mins. The study shows that phosphorylation at Ser5 sites plays a role in normal induction and repression of genes upon NaCl stress. The CTD14 strains harbors a plasmid expressing RPB1 with 14 wild-type CTD repeats. 5A strains carries a plasmid expressing a chimeric RPB1 in which the CTD was composed of 5 repeats of CTD-serine 5 substituted with Ala followed by 7 wild-type-sequenced repeats. The 2A strains carrys 8 repeats of CTD-serine 2 substituted with alanine followed by 7 wild-type-sequenced repeats.
Project description:The modification of Ser 5 is important for the relocalization of RNAP II upon NaCl stress. The CTD14 strains harbors a plasmid expressing RPB1 with 14 wild-type CTD repeats. The 5A strain carries a plasmid expressing a chimeric RPB1 in which the CTD was composed of 5 repeats of CTD-serine 5 substituted with alanine followed by 7 wild-type-sequenced repeats. Two-color fluorescence arrays reporting on Rpb3 localization abundance in strains (input vs. IP) before and at 20 min after a shock with 0.7M NaCl
Project description:In fission yeast, the nuclear-localized Lsk1p-Lsc1p-Lsg1p cyclin dependent kinase complex is required for the reliable execution of cytokinesis and is also required for Ser-2 phosphorylation RNA pol II carboxy terminal domain. To address whether alterations in CTD phosphorylation might selectively alter expression of cytokinesis genes, expression profiling of site-directed CTD mutants was performed. Strains bearing the rpb1-12XCTD and rpb1-12XS2ACTD mutations were grown to mid-log phase in YES media and treated with 0.5uM LatA (or the solvent control, DMSO) for three hours at 30C. Three biological replicates were performed.
Project description:We report calibrated transcriptome of rpb1-CTD-S2A and WT of S. pombe cells. Phosphorylation of the RNA polymerase II (Pol II) C-terminal domain on heptad Y1S2P3T4S5P6S7 coordinates key events during transcription and when its deregulation leads to defects in transcription and RNA processing. Here we report that alanine substitution of all Ser2 in CTD result in increased antisense transcription.
Project description:RPB1, the largest subunit of RNA polymerase II, contains a highly modifiable C-terminal domain (CTD) that consists of variations of a consensus heptad repeat sequence (Y1S2P3T4S5P6S7). The consensus CTD repeat motif and tandem organization represent the ancestral state of eukaryotic RPB1, but across eukaryotes CTDs show considerable diversity in repeat organization and sequence content. These differences may reflect lineage-specific CTD functions mediated by protein interactions. Mammalian CTDs contain eight non-consensus repeats with a lysine in the seventh position (K7). Posttranslational acetylation of these sites was recently shown to be required for proper polymerase pausing and regulation of two growth factor-regulated genes. To investigate the origins and function of RPB1 CTD acetylation (acRPB1), we computationally reconstructed the evolution of the CTD repeat sequence across eukaryotes and analyzed the evolution and function of genes dysregulated when acRPB1 is disrupted. Modeling the evolutionary dynamics of CTD repeat count and sequence content across diverse eukaryotes revealed an expansion of the CTD in the ancestors of Metazoa. The new CTD repeats introduced the potential for acRPB1 due to the appearance of distal repeats with lysine at position seven. This was followed by a further increase in the number of lysine-containing repeats in developmentally complex clades like Deuterostomia. Mouse genes enriched for acRPB1 occupancy at their promoters and genes with significant expression changes when acRPB1 is disrupted are enriched for several functions, such as growth factor response, gene regulation, cellular adhesion, and vascular development. Genes occupied and regulated by acRPB1 show significant enrichment for evolutionary origins in the early history of eukaryotes through early vertebrates. Our combined functional and evolutionary analyses show that RPB1 CTD acetylation was possible in the early history of animals, and that the K7 content of the CTD expanded in specific developmentally complex metazoan lineages. The functional analysis of genes regulated by acRPB1 highlight functions involved in the origin of and diversification of complex Metazoa. This suggests that acRPB1 may have played a role in the success of animals. We used a HA-tagged mouse RPB1 construct in which all K7 residues were substituted with arginines (8KR). This mutation resembles unacetylated lysines by conserving the positive charge at these positions, but preventing acetylation. To examine the potential functions of K7 acetylation in regulating gene expression, we stably expressed wildtype or 8KR HA-RPB1 in murine NIH/3T3 fibroblasts and cultured these cells in media containing α-amanitin. Both were expressed at equivalent levels, but acetylation was present only in wildtype, and not mutant HA-RPB1. We then performed gene expression profiling using the Affymetrix Mouse Gene 1.0 ST microarray with three biological replicates.