Project description:Ribosome profiling was used to investigate how Schizosaccharomcyes pombe cells modulate gene expression in response to osmotic shock
Project description:Condensin plays fundamental roles in chromosome dynamics. In this study, we determined the binding sites of condensin on fission yeast (Schizosaccharomyces pombe) chromosomes at the level of nucleotide sequences using chromatin immunoprecipitation (ChIP) and ChIP-sequencing (ChIP-seq). We found that condensin binds to RNA polymerase I-, II- and III-transcribed genes during both mitosis and interphase, and we focused on pol II constitutive and inducible genes. Accumulation sites for condensin are distinct from those of cohesin and DNA topoisomerase II. Using cell cycle stage- and heat shock-inducible genes, we demonstrate that pol II-mediated transcripts cause condensin accumulation. First, condensin’s enrichment on mitotically activated genes was abolished by deleting the sep1+ gene that encodes an M-phase-specific forkhead transcription factor. Second, by raising the temperature, condensin accumulation was rapidly induced at heat shock protein genes in interphase and even during mid-mitosis. In interphase, condensin accumulates preferentially during the post-replicative phase. pol II-mediated transcription was neither repressed nor activated by condensin, as levels of transcripts per se did not change when mutant condensin failed to associate with chromosomal DNA. However, massive chromosome missegregation occurred, suggesting that abundant pol II transcription may require active condensin prior to proper chromosome segregation.
Project description:Yeast Saccharomyces cerevisiae has been widely used as a model system for studying genomic instability. In this study, heat-shock-induced genomic alterations were explored in the heterozygous diploid yeast strain JSC25-1. In combination of the whole-genome microarray, the patterns of chromosomal instability induced by heat shock could also be explored at a whole genome level. Using this system, we found heat-shock treatment resulted in hundreds-fold higher rate of genomic alterations, including aneuploidy and loss of heterozygosity (LOH).
Project description:DNA array expression analysis comparing RNA transcripts in wild type and hho1 strains before and after a heat-shock from 25 to 37 degrees. Keywords: expression, heat shock
Project description:To determine the transcriptional responses to heat shock of inner ear sensory hair cells and supporting cells, we performed cell-type-specific transcriptional profiling using the RiboTag method, which allows for immunoprecipitation of actively translating mRNAs from specific cell types. RNA-Seq differential gene expression analyses demonstrated that RiboTag identified known cell type-specific markers as well as new markers for hair cells and supporting cells. Gene expression differences suggest that both hair cells and supporting cells exhibit a transcriptional heat shock response. However, hair cells and supporting cells expressed different members of the heat shock protein family in response to heat stress, and supporting cells expressed a larger number of HSPs. Only one HSP, Chaperonin Containing T-Complex Polypeptide 1 Subunit 8, (CCT8) was uniquely induced in hair cells. Together our data indicate that hair cells exhibit a limited but unique heat shock response, and supporting cells exhibit a broader and more robust transcriptional response to protective heat stress.