Project description:In S. pombe, about 5% of genes are meiosis-specific and accumulate little or no mRNA during vegetative growth. Here we use Affymetrix tiling arrays to characterize transcripts in vegetative and meiotic cells. In vegetative cells, many meiotic genes, especially those induced in mid-meiosis, have abundant antisense transcripts. These results suggest that antisense transcription represses sense transcription of meiotic genes in vegetative cells. Although the mechanism(s) of antisense mediated transcription repression need to be further explored, our data indicates that RNAi machinery, such as Rdp1, is not required for repression. Previously, we and others used non-strand specific methods to study splicing regulation of meiotic genes and concluded that 28 mid-meiotic genes are spliced only in meiosis. We now demonstrate that the “unspliced” signal in vegetative cells comes from the antisense RNA, not from unspliced sense RNA, andwe argue against the idea that splicing regulates these mid-meiotic genes. Most of these mid-meiotic genes are induced in mid-meiosis by the forkhead transcription factor Mei4. Interestingly, deletion of a different forkhead transcription factor, Fkh2, allows low levels of sense expression of some mid-meiotic genes in vegetative cells. We propose that expression of mid-meiotic genes is kept tightly off in vegetative cells by two independent ways: antisense transcription and Fkh2 repression.
Project description:Methylation profiles of chr12-16 were generated by meDIP and array hybridisation in 3 cases with maternal uniparental disomy of chromosome 15, and three cases of paternal uniparental disomy of chromosome 15. Comparison of these profiles reveals differentially methylated (imprinted) regions on chromosome 15.
Project description:Body cells in multi-cellular organisms are in the G0 state, in which cells are arrested and terminally differentiated. To understand how the G0 state is maintained, the genes that are specifically expressed or repressed in G0 must be identified, as they control G0. In the fission yeast Schizosaccharomyces pombe, haploid cells are completely arrested under nitrogen source starvation with high viability. We examined the global transcriptome of G0 cells and cells on the course to resume vegetative growth. Approximately 20% of the transcripts of ~5000 genes increased or decreased more than 4-fold in the two-step transitions that occur prior to replication. Of the top 30 abundant transcripts in G0, 23 were replaced by ribosome- and translation-related transcripts in the dividing vegetative state. Eight identified clusters with distinct alteration patterns of ~2700 transcripts were annotated by Gene Ontology. Disruption of 53 genes indicated that 9 of them were necessary to support the proper G0 state. These 9 genes included two C2H2 zinc finger transcription factors, a cyclin-like protein implicated in phosphorylation of RNA polymerase II, two putative autophagy regulators, a G-protein activating factor, and two CBS domain proteins, possibly involved in AMP-activated kinase. Keywords: Keywards: Time course, Nitrogen starvation, G0 state, Nitrogen replenishment, Nutrient signal, Cell cycle, Cell proliferation
Project description:Puf3 is a RNA-binding protein, a member of the conserved Puf-protein family. Combining different functional genomics data, we have analyzed the role of Puf3 in post-transcriptional gene regulation in S. pombe. We present data on Puf3 interacting proteins and regulatory mRNA targets.
