Homologs of these genes have been identified by us in mouse, maize and other fungi. We have shown that one biochemical function of Rad52 protein is to enhance DNA strand annealing. MEC1 is a homolog of the human ATM gene, which is mutated in ataxia-telangiectasia patients. A genetic suppressor of mec1 and mec2 has been identified that separates the essential function from both recombination and checkpoint control. Finally, using the entire genome sequence of an organism, we are developing methods to create complete gene disruption libraries as well as two-hybrid libraries to permit functional analyses on a genomic scale.
Gene conversion plays the major role in controlling the stability of large tandem repeats in yeast.
DNA strand annealing is promoted by the yeast Rad52 protein. Holliday junctions accumulate in DNA replication mutants via a RecA homolog-independent mechanism. Cell, in press .