DSC1-MCB regulation of meiotic transcription in Schizosaccharomyces pombe

Abstract

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 lu 1 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.