Transcription during meiosis in the fission yeast Schizosaccharomyces pombe

Cunliffe, Lesley (2004) Transcription during meiosis in the fission yeast Schizosaccharomyces pombe. PhD thesis, University of Glasgow.

Abstract

The meiotic cell cycle is the process by which diploid organisms divide to produce haploid gametes and consists of one round of DNA replication followed by two successive nuclear divisions. In the fission yeast, Schizosaccharomyces pombe, meiosis is initiated from G1 phase and involves a complex series of cellular events that lead to the production of four haploid ascospores. The periodic regulation of gene expression is an important mechanism of control of both mitotic- and meiotic-cell-cycle progression. During the mitotic cell cycle of fission yeast a number of genes, including cdc22+, cdc18+ and cdt1+, are expressed specifically at the G1-S phase boundary. These genes are known to be under the control of MCB (MluI cell-cycle box) upstream-activating-sequence motifs and the MBF (MCB binding factor; also known as DSC1) complex. Here we show that control of gene expression during pre-meiotic G1-S-phase is mediated by an MBF-related transcription-factor complex acting upon similar MCB promoter motifs. Several genes, including rec11+, rec11+, cdc18+, and cdc22+, which contain MCB motifs in their promoter regions, are shown to be coordinately regulated during pre-meiotic S-phase. These genes can be divided into 'mitotic and meiotic' and 'meiotic specific' groups, which contain related but distinct arrangements of MCB motifs. MCB motifs are shown to be physiologically relevant during the meiotic cell cycle and to confer meiotic-specific transcription to a heterologous reporter gene. An MBF-like transcription factor complex that binds to MCB motifs is identified in meiotic cells. The effect of mutating and over-expressing individual components of MBF (cdc10+, res1+, res2+, rep1+ and rep2+) on cdc22+, rec8+ and ree11+ transcription during meiosis was examined. We found that cdc10+, res2+ and rep1+ are required for meiotic transcription, while rest has no role in this process. Surprisingly, manipulation of the mitotic-specific rep2+ gene had an effect on 'meiotic specific' but not 'mitotic and meiotic' MCB-regulated transcription during the meiotic cell cycle. This indicates that Rep2p might have a role in allowing the MBF complex to distinguish between 'mitotic and meiotic' and 'meiotic specific' MCB motifs. This work is the first demonstration in yeast of a role for MCB motifs in control of transcription during meiosis, and identifies a meiotic MBF-like transcription-factor complex.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Colleges/Schools: College of Medical Veterinary and Life Sciences
• Supervisor's Name: McInerny, Dr. Chris
• Date of Award: 2004
• Depositing User: Mrs Monika Milewska-Fiertek
• Unique ID: glathesis:2004-30900
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 12 Oct 2018 15:02
• Last Modified: 07 Jun 2021 15:36
• URI: https://theses.gla.ac.uk/id/eprint/30900

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