Reconstitution of recombination-associated DNA synthesis with human proteins.

ABSTRACT: The repair of DNA breaks by homologous recombination is a high-fidelity process, necessary for the maintenance of genome integrity. Thus, DNA synthesis associated with recombinational repair must be largely error-free. In this report, we show that human DNA polymerase delta (?) is capable of robust DNA synthesis at RAD51-mediated recombination intermediates dependent on the processivity clamp PCNA. Translesion synthesis polymerase eta (?) also extends these substrates, albeit far less processively. The single-stranded DNA binding protein RPA facilitates recombination-mediated DNA synthesis by increasing the efficiency of primer utilization, preventing polymerase stalling at specific sequence contexts, and overcoming polymerase stalling caused by topological constraint allowing the transition to a migrating D-loop. Our results support a model whereby the high-fidelity replicative DNA polymerase ? performs recombination-associated DNA synthesis, with translesion synthesis polymerases providing a supportive role as in normal replication.

SUBMITTER: Sneeden JL 

PROVIDER: S-EPMC3643601 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature