Premature Cdk1/Cdc5/Mus81 pathway activation induces aberrant replication and deleterious crossover
نویسندگان
چکیده
The error-free DNA damage tolerance (DDT) pathway is crucial for replication completion and genome integrity. Mechanistically, this process is driven by a switch of templates accompanied by sister chromatid junction (SCJ) formation. Here, we asked if DDT intermediate processing is temporarily regulated, and what impact such regulation may have on genome stability. We find that persistent DDT recombination intermediates are largely resolved before anaphase through a G2/M damage checkpoint-independent, but Cdk1/Cdc5-dependent pathway that proceeds via a previously described Mus81-Mms4-activating phosphorylation. The Sgs1-Top3- and Mus81-Mms4-dependent resolution pathways occupy different temporal windows in relation to replication, with the Mus81-Mms4 pathway being restricted to late G2/M. Premature activation of the Cdk1/Cdc5/Mus81 pathway, achieved here with phosphomimetic Mms4 variants as well as in S-phase checkpoint-deficient genetic backgrounds, induces crossover-associated chromosome translocations and precocious processing of damage-bypass SCJ intermediates. Taken together, our results underscore the importance of uncoupling error-free versus erroneous recombination intermediate processing pathways during replication, and establish a new paradigm for the role of the DNA damage response in regulating genome integrity by controlling crossover timing.
منابع مشابه
Dbf4‐dependent kinase and the Rtt107 scaffold promote Mus81‐Mms4 resolvase activation during mitosis
DNA repair by homologous recombination is under stringent cell cycle control. This includes the last step of the reaction, disentanglement of DNA joint molecules (JMs). Previous work has established that JM resolving nucleases are activated specifically at the onset of mitosis. In case of budding yeast Mus81-Mms4, this cell cycle stage-specific activation is known to depend on phosphorylation b...
متن کاملCdc28-Dependent Regulation of the Cdc5/Polo Kinase
Polo kinase is activated as cells enter mitosis and plays a central role in coordinating diverse mitotic events, yet the mechanisms leading to activation of Polo kinase are poorly understood . Work in Xenopus meiotic cell cycles has suggested that Polo kinase functions in a pathway that helps trigger activation of Cdk1 . However, studies in other organisms have suggested that activation of Polo...
متن کاملHaploinsufficiency of the Mus81–Eme1 endonuclease activates the intra-S-phase and G2/M checkpoints and promotes rereplication in human cells
The Mus81-Eme1 complex is a structure-specific endonuclease that preferentially cleaves nicked Holliday junctions, 3'-flap structures and aberrant replication fork structures. Mus81-/- mice have been shown to exhibit spontaneous chromosomal aberrations and, in one of two models, a predisposition to cancers. The molecular mechanisms underlying its role in chromosome integrity, however, are large...
متن کاملOncogenes induce genotoxic stress by mitotic processing of unusual replication intermediates
Oncogene-induced DNA replication stress activates the DNA damage response (DDR), a crucial anticancer barrier. DDR inactivation in these conditions promotes genome instability and tumor progression, but the underlying molecular mechanisms are elusive. We found that overexpression of both Cyclin E and Cdc25A rapidly slowed down replication forks and induced fork reversal, suggestive of increased...
متن کاملThe MUS81 endonuclease is essential for telomerase negative cell proliferation.
A substantial number of human tumors (approximately 10%) are telomerase negative, and cells in such tumors have been proposed to maintain telomere length by the alternative lengthening of telomeres (ALT) pathway. Although details of the molecular mechanism of ALT are largely unknown, previous studies have shown that telomere homologous recombination (HR) is implicated in the ALT pathway. MUS81 ...
متن کامل