The DNA replication checkpoint directly regulates MBF-dependent G1/S transcription.
The DNA replication checkpoint transcriptionally upregulates genes that allow cells to adapt to and survive replication stress. Our results show that, in the fission yeast Schizosaccharomyces pombe, the replication checkpoint regulates the entire G(1)/S transcriptional program by directly regulating MBF, the G(1)/S transcription factor. Instead of initiating a checkpoint-specific transcriptional program, the replication checkpoint targets MBF to maintain the normal G(1)/S transcriptional program during replication stress. We propose a mechanism for this regulation, based on in vitro phosphorylation of the Cdc10 subunit of MBF by the Cds1 replication-checkpoint kinase. Replacement of two potential phosphorylation sites with phosphomimetic amino acids suffices to promote the checkpoint transcriptional program, suggesting that Cds1 phosphorylation directly regulates MBF-dependent transcription. The conservation of MBF between fission and budding yeast, and recent results implicating MBF as a target of the budding yeast replication checkpoint, suggests that checkpoint regulation of the MBF transcription factor is a conserved strategy for coping with replication stress. Furthermore, the structural and regulatory similarity between MBF and E2F, the metazoan G(1)/S transcription factor, suggests that this checkpoint mechanism may be broadly conserved among eukaryotes.
Dutta
Chaitali
C
Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Patel
Prasanta K
PK
Rosebrock
Adam
A
Oliva
Anna
A
Leatherwood
Janet
J
Rhind
Nicholas
N
D018797:Cell Cycle Proteins / Q000378:metabolism*; D064447:Checkpoint Kinase 2; D004261:DNA Replication; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D018797:Cell Cycle Proteins; C489911:DSC1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; D064447:Checkpoint Kinase 2; C578636:Cds1 protein, S pombe; D017346:Protein Serine-Threonine Kinases