Regulation of gene expression during M-G1-phase in fission yeast through Plo1p and forkhead transcription factors.
In fission yeast the expression of several genes during M-G1 phase is controlled by binding of the PCB binding factor (PBF) transcription factor complex to Pombe cell cycle box (PCB) promoter motifs. Three components of PBF have been identified, including two forkhead-like proteins Sep1p and Fkh2p, and a MADS-box-like protein, Mbx1p. Here, we examine how PBF is controlled and reveal a role for the Polo kinase Plo1p. plo1(+) shows genetic interactions with sep1(+), fkh2(+) and mbx1(+), and overexpression of a kinase-domain mutant of plo1 abolishes M-G1-phase transcription. Plo1p binds to and directly phosphorylates Mbx1p, the first time a Polo kinase has been shown to phosphorylate a MADS box protein in any organism. Fkh2p and Sep1p interact in vivo and in vitro, and Fkh2p, Sep1p and Plo1p contact PCB promoters in vivo. However, strikingly, both Fkh2p and Plo1p bind to PCB promoters only when PCB-controlled genes are not expressed during S- and G2-phase, whereas by contrast Sep1p contacts PCBs coincident with M-G1-phase transcription. Thus, Plo1p, Fkh2p and Sep1p control M-G1-phase gene transcription through a combination of phosphorylation and cell-cycle-specific DNA binding to PCBs.
Division of Biochemistry and Molecular Biology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
Kyriaki
K
Papadopoulou
Szu Shien
SS
Ng
Hiroyuki
H
Ohkura
Marco
M
Geymonat
Steven G
SG
Sedgwick
Christopher J
CJ
McInerny
D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002455:Cell Division; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D051858:Forkhead Transcription Factors / Q000235:genetics* / Q000378:metabolism; D016193:G1 Phase; D015966:Gene Expression Regulation, Fungal; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D051858:Forkhead Transcription Factors; D011994:Recombinant Proteins; D029702:Schizosaccharomyces pombe Proteins; C121803:sep1 protein, S pombe; C501407:Plo1 protein, S pombe; D017346:Protein Serine-Threonine Kinases