The Mating-Type Proteins of Fission Yeast Induce Meiosis by Directly Activating mei3 Transcription
AUTOR(ES)
van Heeckeren, Willem J.
FONTE
American Society for Microbiology
RESUMO
Cell type control of meiotic gene regulation in the budding yeast Saccharomyces cerevisiae is mediated by a cascade of transcriptional repressors, a1-α2 and Rme1. Here, we investigate the analogous regulatory pathway in the fission yeast Schizosaccharomyces pombe by analyzing the promoter of mei3, the single gene whose expression is sufficient to trigger meiosis. The mei3 promoter does not appear to contain a negative regulatory element that represses transcription in haploid cells. Instead, correct regulation of mei3 transcription depends on a complex promoter that contains at least five positive elements upstream of the TATA sequence. These elements synergistically activate mei3 transcription, thereby constituting an on-off switch for the meiosis pathway. Element C is a large region containing multiple sequences that resemble binding sites for Mc, an HMG domain protein encoded by the mating-type locus. The function of element C is extremely sensitive to spacing changes but not to linker-scanning mutations, suggesting the possibility that Mc functions as an architectural transcription factor. Altered-specificity experiments indicate that element D interacts with Pm, a homeodomain protein encoded by the mating-type locus. This indicates that Pm functions as a direct activator of the meiosis pathway, whereas the homologous mating-type protein in S. cerevisiae (α2) functions as a repressor. Thus, despite the strong similarities between the mating-type loci of S. cerevisiae and S. pombe, the regulatory logic that governs the tight control of the key meiosis-inducing genes in these organisms is completely different.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=109313Documentos Relacionados
- The product of the mei3+ gene, expressed under control of the mating-type locus, induces meiosis and sporulation in fission yeast.
- Regulation of Mating and Meiosis in Yeast by the Mating-Type Region
- Rearrangements of the transposable mating-type cassettes of fission yeast.
- The pat1 protein kinase controls transcription of the mating-type genes in fission yeast.
- Regulation of yeast mating-type interconversion: feedback control of HO gene expression by the mating-type locus.