XB-ART-41287Cell Cycle March 15, 2010; 9 (6): 1156-66.
Xenopus DNA2 is a helicase/nuclease that is found in complexes with replication proteins And-1/Ctf4 and Mcm10 and DSB response proteins Nbs1 and ATM.
We have used the Xenopus laevis egg extract system to study the roles of vertebrate Dna2 in DNA replication and double-strand-break (DSB) repair. We first establish that Xenopus Dna2 is a helicase, as well as a nuclease. We further show that Dna2 is a nuclear protein that is actively recruited to DNA only after replication origin licensing. Dna2 co-localizes in foci with RPA and is found in a complex with replication fork components And-1 and Mcm10. Dna2 interacts with the DSB repair and checkpoint proteins Nbs1 and ATM. We also determine the order of arrival of ATM, MRN, Dna2, TopBP1, and RPA to duplex DNA ends and show that it is the same both in S phase and M phase extracts. Interestingly, Dna2 can bind to DNA ends independently of MRN, but efficient nucleolytic resection, as measured by RPA recruitment, requires both MRN and Dna2. The nuclease activity of Mre11 is required, since its inhibition delays both full Dna2 recruitment and resection. Dna2 depletion inhibits but does not block resection, and Chk1 and Chk2 induction occurs in the absence of Dna2.
PubMed ID: 20237432
PMC ID: PMC3059328
Article link: Cell Cycle
Genes referenced: atm chek1 chek2 dna2 mcm10 mre11 nbn rpa1 topbp1 wdhd1
Antibodies: Atm Ab2 Cdc6 Ab1 Mcm2 Ab2 Mcm3 Ab1 Rpa1 Ab1
References [+] :
Andegeko, Nuclear retention of ATM at sites of DNA double strand breaks. 2001, Pubmed