Project description:Genomic surveys of yeast hybrid species isolated from the wild and from human-related environment, aimed at the reconstruction of the natural evolution of Saccharomyces spp. evolution
Project description:We developed an artificial genome evolution system, which we termed ‘TAQing’, by introducing multiple genomic DNA double-strand breaks using a heat-activatable endonuclease in mitotic yeast. The heat-activated endonuclease, TaqI, induced random DSBs, which resulted in diverse types of chromosomal rearrangements including translocations. Array comparative genomic hybridization (aCGH) analysis was performed with cell-fused Saccharomyces cerevisiae strains induced genome evolution by TAQing system. Some of copy number variations (CNVs) induced by massive genome rearrangements were detected in the TAQed yeast strains.
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:RPCC (RNA pol II ChIP-on-chip) experiments with different mutants that affect to the accumulation of non active RNA pol II along the yeast genome. Keywords: ChIP-chip
Project description:Diversification of histone variants is marked by the acquisition of distinct motifs and features through convergent evolution. H2A variants tend to be associated with defined domains of the genome. Specific features distinguish H2A variants in eukaryotes but whether evolution of these features predated the evolution of deposition mechanisms or vice-versa has remained unclear.In flowering plants, the variant H2A.W is tightly associated with heterochromatin. H2A.W evolved in land plants through acquisition of an extended C-terminal tail enriched with basic residues and a KSPK motif. Here, we used a synthetic approach in fission yeast, which lacks H2A.W and its dedicated deposition mechanism, to recapitulate the evolutionary steps that led to H2A.W and to assess the impact of the KSPK motif on heterochromatin composition and its properties. In conclusion, the acquisition of the KSPK motif in yeast promotes chromatin properties that are comparable to the properties and function of H2A.W in plant heterochromatin. Hence, the KSPK motif could have been selected before the evolution of direct heterochromatin deposition mechanisms. We propose that the acquisition of functional histone variant motifs can confer properties which affect only specific chromatin states, thereby driving the evolution of specific deposition mechanisms.
