Cyclin-dependent kinase suppression by WEE1 kinase protects the genome through control of replication initiation and nucleotide consumption.
Activation of oncogenes or inhibition of WEE1 kinase deregulates cyclin-dependent kinase (CDK) activity and leads to replication stress; however, the underlying mechanism is not understood. We now show that elevation of CDK activity by inhibition of WEE1 kinase rapidly increases initiation of replication. This leads to nucleotide shortage and reduces replication fork speed, which is followed by SLX4/MUS81-mediated DNA double-strand breakage. Fork speed is normalized and DNA double-strand break (DSB) formation is suppressed when CDT1, a key factor for replication initiation, is depleted. Furthermore, addition of nucleosides counteracts the effects of unscheduled CDK activity on fork speed and DNA DSB formation. Finally, we show that WEE1 regulates the ionizing radiation (IR)-induced S-phase checkpoint, consistent with its role in control of replication initiation. In conclusion, these results suggest that deregulated CDK activity, such as that occurring following inhibition of WEE1 kinase or activation of oncogenes, induces replication stress and loss of genomic integrity through increased firing of replication origins and subsequent nucleotide shortage.
Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark.
Halfdan
H
Beck
Viola
V
Nähse-Kumpf
Marie Sofie Yoo
MS
Larsen
Karen A
KA
O'Hanlon
Sebastian
S
Patzke
Christian
C
Holmberg
Jakob
J
Mejlvang
Anja
A
Groth
Olaf
O
Nielsen
Randi G
RG
Syljuåsen
Claus Storgaard
CS
Sørensen
D016203:CDC2 Protein Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002460:Cell Line; D053903:DNA Breaks, Double-Stranded; D004261:DNA Replication; D015894:Genome, Human; D042822:Genomic Instability; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism*; D009711:Nucleotides / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D045522:Recombinases / Q000378:metabolism; D059807:S Phase Cell Cycle Checkpoints / Q000528:radiation effects
C467199:CDT1 protein, human; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D009711:Nucleotides; D045522:Recombinases; D011505:Protein-Tyrosine Kinases; C499349:WEE1 protein, human; D016203:CDC2 Protein Kinase; C542319:SLX4 protein, human