The MluI cell cycle box (MCB) motifs, but not damage-responsive elements (DREs), are responsible for the transcriptional induction of the rhp51+ gene in response to DNA replication stress.
DNA replication stress induces the transcriptional activation of rhp51+, a fission yeast recA homolog required for repair of DNA double strand breaks. However, the mechanism by which DNA replication stress activates rhp51+ transcription is not understood. The promoter region of rhp51+ contains two damage-responsive elements (DREs) and two MluI cell cycle box (MCB) motifs. Using luciferase reporter assays, we examined the role of these elements in rhp51+ transcription. The full-length rhp51+ promoter and a promoter fragment containing MCB motifs only, but not a fragment containing DREs, mediated transcriptional activation upon DNA replication stress. Removal of the MCB motifs from the rhp51+ promoter abolished the induction of rhp51+ transcription by DNA replication stress. Consistent with a role for MCB motifs in rhp51+ transcription activation, deletion of the MBF (MCB-binding factor) co-repressors Nrm1 and Yox1 precluded rhp51+ transcriptional induction in response to DNA replication stress. Using cells deficient in checkpoint signaling molecules, we found that the Rad3-Cds1/Chk1 pathway partially mediated rhp51+ transcription in response to DNA replication stress, suggesting the involvement of unidentified checkpoint signaling pathways. Because MBF is critical for G1/S transcription, we examined how the cell cycle affected rhp51+ transcription. The transcription of rhp51+ and cdc18+, an MBF-dependent G1/S gene, peaked simultaneously in synchronized cdc25-22 cells. Furthermore, DNA replication stress maintained transcription of rhp51+ similarly to cdc18+. Collectively, these results suggest that MBF and its regulators mediate rhp51+ transcription in response to DNA replication stress, and underlie rhp51+ transcription at the G1/S transition.
Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan.
Wugangerile
W
Sartagul
Department of Oncology, First Affiliated Hospital of Liaoning Medical University, Jinzhou, China; Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan.
Xin
X
Zhou
Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan.
Yuki
Y
Yamada
Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan.
Ning
N
Ma
Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Japan.
Katsunori
K
Tanaka
Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan.
Tomoyuki
T
Furuyashiki
Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan.
Yan
Y
Ma
D002453:Cell Cycle / Q000235:genetics; D018797:Cell Cycle Proteins / Q000378:metabolism; D064447:Checkpoint Kinase 2 / Q000378:metabolism; D004249:DNA Damage; D004261:DNA Replication; D018398:Homeodomain Proteins / Q000378:metabolism; D059372:Nucleotide Motifs; D011401:Promoter Regions, Genetic; D051135:Rad51 Recombinase / Q000235:genetics*; D012097:Repressor Proteins / Q000378:metabolism; D020218:Response Elements; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological; D014158:Transcription, Genetic
D018797:Cell Cycle Proteins; D018398:Homeodomain Proteins; C513403:Nrm1 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C080459:Yox1 protein, S cerevisiae; D064447:Checkpoint Kinase 2; C578636:Cds1 protein, S pombe; C456840:rad3 protein, S pombe; D051135:Rad51 Recombinase