Purification and Characterization of DNA Polymerase α-Associated Replication Protein A-Dependent Yeast DNA Helicase A†

Biochemistry ◽  
1997 ◽  
Vol 36 (43) ◽  
pp. 13270-13276 ◽  
Author(s):  
Subhasis B. Biswas ◽  
Pei Hua Chen ◽  
Esther E. Biswas
2001 ◽  
Vol 276 (21) ◽  
pp. 18235-18242 ◽  
Author(s):  
Giovanni Maga ◽  
Isabelle Frouin ◽  
Silvio Spadari ◽  
Ulrich Hübscher

2000 ◽  
Vol 20 (9) ◽  
pp. 3086-3096 ◽  
Author(s):  
Lee Zou ◽  
Bruce Stillman

ABSTRACT In Saccharomyces cerevisiae, replication origins are activated with characteristic timing during S phase. S-phase cyclin-dependent kinases (S-CDKs) and Cdc7p-Dbf4p kinase are required for origin activation throughout S phase. The activation of S-CDKs leads to association of Cdc45p with chromatin, raising the possibility that Cdc45p defines the assembly of a new complex at each origin. Here we show that both Cdc45p and replication protein A (RPA) bind to Mcm2p at the G1-S transition in an S-CDK-dependent manner. During S phase, Cdc45p associates with different replication origins at specific times. The origin associations of Cdc45p and RPA are mutually dependent, and both S-CDKs and Cdc7p-Dbf4p are required for efficient binding of Cdc45p to origins. These findings suggest that S-CDKs and Cdc7p-Dbf4p promote loading of Cdc45p and RPA onto a preformed prereplication complex at each origin with preprogrammed timing. TheARS1 association of Mcm2p, but not that of the origin recognition complex, is diminished by disruption of the B2 element ofARS1, a potential origin DNA-unwinding element. Cdc45p is required for recruiting DNA polymerase α onto chromatin, and it associates with Mcm2p, RPA, and DNA polymerase ɛ only during S phase. These results suggest that the complex containing Cdc45p, RPA, and MCMs is involved in origin unwinding and assembly of replication forks at each origin.


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