Cdc24 is essential for long-range end resection in the repair of dsDNA breaks [Metabolism]

October 11th, 2016 by Zhang, H., Hua, Y., Li, R., Kong, D.

Double-stranded DNA breaks (DSBs) are highly detrimental DNA lesions, which may be repaired by the homologous recombination-mediated repair pathway. The 5 prime to 3 prime direction of long-range end resection on one DNA strand, in which 3 prime-single-strand DNA overhangs are created from broken DNA ends, is an essential step in this pathway. Dna2 has been demonstrated as an essential nuclease in this event, but the molecular mechanism how Dna2 is recruited to DNA break sites in vivo is not elucidated. In this study, a novel recombination factor called Cdc24 was identified in fission yeast. We demonstrated that Cdc24 localizes to DNA break sites during the repair of DNA breaks and is an essential factor for long-range end resection. We also determined that Cdc24 plays a direct role in recruiting Dna2 to DNA break sites through its interaction with Dna2 and replication protein A (RPA). Further, this study revealed that RPA acts as a foundation in assembling the machinery for long-range end resection by its essential role in recruiting Cdc24 and Dna2 to DNA break sites. These results define Cdc24 as an essential factor for long-range end resection in the repair of DSBs, opening the door for further investigations into the enzymes involved in long-range end resection for DSB repair.