UNASSIGNED: Single-strand annealing (SSA) is an important homologous recombination mechanism that repairs DNA double strand breaks (DSBs) occurring between closely spaced repeat sequences. During SSA, the DSB is acted upon by exonucleases to reveal complementary sequences that anneal and are then repaired through tail clipping, DNA synthesis, and ligation steps. In @entity375 , the Msh DNA mismatch recognition complex and the @entity13568 helicase act to suppress SSA between divergent sequences by binding to mismatches present in heteroduplex DNA intermediates and triggering a DNA unwinding mechanism known as heteroduplex rejection. Using @entity375 as a model, we have identified new factors and regulatory steps in heteroduplex rejection during SSA. First we showed that Top3- @entity50860 , a topoisomerase complex that interacts with @entity13568 , is required for heteroduplex rejection. Second, we found that the replication processivity clamp PCNA is dispensable for heteroduplex rejection, but is important for repairing mismatches formed during SSA. Third, we showed that modest overexpression of @entity69102 results in a significant increase in heteroduplex rejection; this increase is due to a compromise in @entity9870 - @entity69103 function required for the clipping of 3' tails. Thus 3' tail clipping during SSA is a critical regulatory step in the repair vs. rejection decision; rejection is favored before the 3' tails are clipped. Unexpectedly, @entity69102 overexpression, through interactions with PCNA, disrupted heteroduplex rejection between divergent sequences in another recombination substrate. These observations illustrate the delicate balance that exists between repair and replication factors to optimize genome stability.

A Delicate Balance Between Repair and Replication Factors Regulates Recombination Between Divergent DNA Sequences in XXXX .

@entity13568 :: ('855228(Tax:4932)', 'Gene') :: ['Sgs1'] @entity50860 :: ('856083(Tax:4932)', 'Gene') :: ['Rmi1'] @entity69103 :: ('850454(Tax:4932)', 'Gene') :: ['Msh3'] @entity69102 :: ('851671(Tax:4932)', 'Gene') :: ['Msh6'] @entity9870 :: ('854063(Tax:4932)', 'Gene') :: ['Msh2'] @entity375 :: ('4932', 'Species') :: ["baker's yeast"]
@entity375 :: (4932,Species) :: ['Saccharomyces cerevisiae']
