A novel role of the Dna2 translocase function in DNA break resection.

摘要: DNA double-strand break repair by homologous recombination entails nucleolytic resection of the 5' strand at ends. Dna2, a flap endonuclease with 5'-3' helicase activity, is involved in process. The Dna2 activity has been implicated Okazaki fragment processing during replication but thought to be dispensable for end resection. Unexpectedly, we found requirement function budding yeast cells lacking exonuclease 1. Biochemical analysis reveals that ATP hydrolysis-fueled translocation on ssDNA facilitates cleavage near single-strand-double junction while attenuating 3' incision. Accordingly, hydrolysis-defective dna2-K1080E mutant less able generate long products reconstituted system. Our study thus previously unrecognized role translocase and imposition specificity