DSC1-MCB regulation of meiotic transcription in Schizosaccharomyces pombe.

Meiosis is initiated from the G1 phase of the mitotic cell cycle, and consists of pre-meiotic S-phase followed by two successive nuclear divisions. Here we show that control of gene expression during pre-meiotic S-phase in the fission yeast Schizosaccharomyces pombe is mediated by a DNA synthesis control-like transcription factor complex (DSC1), which acts upon M lu1 cell cycle box (MCB) promoter motifs. Several genes, including rec8+, rec11+, cdc18+, and cdc22+, which contain MCB motifs in their promoter regions, are found to be co-ordinately regulated during pre-meiotic S-phase. Both synthetic and native MCB motifs are shown to confer meiotic-specific transcription on a heterologous reporter gene. A DSC1-like transcription factor complex that binds to MCB motifs was also identified in meiotic cells. The effect of mutating and over-expressing individual components of DSC1 (cdc10+, res1+, res2+, rep1+ and rep2+) on the transcription of cdc22+, rec8+ and rec11+ during meiosis was examined. We found that cdc10+, res2+, rep1+ and rep2+ are required for correct meiotic transcription, while res1+ is not required for this process. This work demonstrates a role for MCB motifs and a DSC1-like transcription factor complex in controlling transcription during meiosis in fission yeast, and suggests a mechanism for how this specific expression occurs.