We also show that MDM2-mediated H3K4 methylation is checkpoint-dependent, as it can be inhibited by caffeine (Physique 8C). Our data signify that a compromised checkpoint response would allow an increase in untimely origin firing by MDM2. cells. Consistently, inhibition of cyclin-dependent kinases, known to activate DNA replication origins during firing, inhibits MDM2-mediated induction of chk1 […]