Plo1+ regulates gene transcription at the M-G1 interval during the fission yeast mitotic cell cycle

Abstract

The regulation of gene expression plays an important part in cell cycle controls. We describe the molecular machinery that co-ordinates gene transcription at the M-G1 interval during the fission yeast mitotic cell cycle. A sequence is identified in the cdc15+ promoter that we call a PCB (pombe cell cycle box), which confers M-G1-specific transcription. Sequences similar to the PCB are present in the promoters of seven other genes, spo12+, cdc19+, fin1+, sid2+, ppb1+, mid1+/dmf1+ and plo1+, which we find to be transcribed at M-G1. A transcription factor complex is identified that binds to the PCB sequence, which we name PBF, for PCB-binding factor. Finally, we show that PBF binding activity and consequent gene transcription are regulated by the Plo1p protein kinase, thus invoking a potential auto-feedback loop mechanism that regulates mitotic gene transcription and passage through septation and cytokinesis.