Cdc14 phosphatase counteracts Cdk-dependent Dna2 phosphorylation to inhibit resection during recombinational DNA repair

The Cdk stimulates resection of DNA double-strand breaks ends to generate ssDNA molecules needed for recombinational DNA repair. Here we show that lack of the Cdk-counteracting phosphatase Cdc14 renders cells to abnormally extended resected tracts at the DNA break ends, involving the phosphatase in the inhibition of resection. Over-resection in the absence of Cdc14 activity is bypassed when the exonuclease Dna2 is inactivated or when its Cdk consensus sites are mutated, indicating that the phosphatase restrains resection by acting through this nuclease. Accordingly, mitotic activated Cdc14 promotes the dephosphorylation of Dna2 to exclude it from the DNA lesion. Cdc14-dependent resection inhibition is essential to sustain DNA re-synthesis, thus ensuring the appropriate length, frequency, and distribution of the gene conversion tracts. These results establish a new role for Cdc14 in controlling the extent of resection through the regulation of Dna2 and demonstrate that the accumulation of excessive long ssDNA affects the accurate repair of the broken DNA by homologous recombination.