ABSTRACT: A new transcription factor for mitosis: In S. pombe, the RFX transcription factor Sak1 works with forkhead factors to regulate mitotic expression (array)
Project description:A new transcription factor for mitosis: In S. pombe, the RFX transcription factor Sak1 works with forkhead factors to regulate mitotic expression (ChIP-Seq)
Project description:Many genes are transcriptionally regulated as a function of the cell cycle; genes needed for mitosis are strongly cell cycle regulated. From yeasts to humans, forkhead transcription factors are involved in mitotic gene expression. However, the mechanisms of regulation are unclear, especially since forkhead transcription factors can be activators or repressors, and often function in concert with other proteins. Here, we study mitotic regulation in the fission yeast S. pombe. We find that the forkhead transcription factor Fkh2 is a repressor of many mitotic genes, while a different forkhead transcription factor, Sep1, is an activator of a subset of these genes. The activator of the majority of mitotic genes appears to be Sak1, a transcription factor of the RFX family, which has not previously been implicated in cell cycle control. 24 samples were analyzed. Control for all experiments was the same. The samples are representative of selective spore germination in S. pombe (time course arrays for the WT as well as the mentioned mutants) or the sak1-891 ts strain restrictive temperature time course (WT and ts strain)
Project description:Many genes are transcriptionally regulated as a function of the cell cycle; genes needed for mitosis are strongly cell cycle regulated. From yeasts to humans, forkhead transcription factors are involved in mitotic gene expression. However, the mechanisms of regulation are unclear, especially since forkhead transcription factors can be activators or repressors, and often function in concert with other proteins. Here, we study mitotic regulation in the fission yeast S. pombe. We find that the forkhead transcription factor Fkh2 is a repressor of many mitotic genes, while a different forkhead transcription factor, Sep1, is an activator of a subset of these genes. The activator of the majority of mitotic genes appears to be Sak1, a transcription factor of the RFX family, which has not previously been implicated in cell cycle control. 3 test samples were analyzed; 1 control (no-tag) sample was processed (each sample has 2 replicate experiments)
Project description:A new transcription factor for mitosis: In S. pombe, the RFX transcription factor Sak1 works with forkhead factors to regulate mitotic expression
Project description:Mitotic genes are one of the most strongly oscillating groups of genes in the eukaryotic cell cycle. Understanding the regulation of mitotic gene expression is a key issue in cell cycle control but is poorly understood in most organisms. Here, we find a new mitotic transcription factor, Sak1, in the fission yeast S. pombe. Sak1 belongs to the RFX family of transcription factors, which have not previously been connected to cell cycle control. Sak1 binds upstream of mitotic genes in close proximity to Fkh2, a forkhead transcription factor previously implicated in regulation of mitotic genes. We show that Sak1 is the major activator of mitotic gene expression and also confirm the role of Fkh2 as the opposing repressor. Sep1, another forkhead transcription factor, is an activator for a small subset of mitotic genes involved in septation. From yeasts to humans, forkhead transcription factors are involved in mitotic gene expression, and it will be interesting to see whether RFX transcription factors may also be involved in other organisms.
Project description:Mitotic genes are one of the most strongly oscillating groups of genes in the eukaryotic cell cycle. Understanding the regulation of mitotic gene expression is a key issue in cell cycle control but is poorly understood in most organisms. Here, we find a new mitotic transcription factor, Sak1, in the fission yeast S. pombe. Sak1 belongs to the RFX family of transcription factors, which have not previously been connected to cell cycle control. Sak1 binds upstream of mitotic genes in close proximity to Fkh2, a forkhead transcription factor previously implicated in regulation of mitotic genes. We show that Sak1 is the major activator of mitotic gene expression and also confirm the role of Fkh2 as the opposing repressor. Sep1, another forkhead transcription factor, is an activator for a small subset of mitotic genes involved in septation. From yeasts to humans, forkhead transcription factors are involved in mitotic gene expression, and it will be interesting to see whether RFX transcription factors may also be involved in other organisms.
Project description:Mononucleosomal DNA analysis of atf1D and pcr1D mutants of Schizosaccharomyces pombe and transcription analysis of exponential wild type 972 h-, atf1D, pcr1D and mitotic diploid pat1.114, and synchronous diploid pat1.114 at 0h, 3h and 5h into meiosis
Project description:Mononucleosomal DNA analysis of atf1D and pcr1D mutants of Schizosaccharomyces pombe and transcription analysis of exponential wild type 972 h-, atf1D, pcr1D and mitotic diploid pat1.114, and synchronous diploid pat1.114 at 0h, 3h and 5h into meiosis Mononucleosomal DNA vs. genomic input DNA in wildtype 972 h-, atf1D and pcr1D mutants of S. pombe was hybridized to Affymetrix GeneChip 1.0FR tiling microarrays (GPL7715). Total RNA for genome-wide transcription analysis from exponential wild type 972 h-, atf1D, pcr1D and mitotic diploid pat1.114 cells, and from synchronous diploid pat1.114 at 0h, 3h and 5h into meiosis was hybridized to the same microarrays.
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.
