Homologous and homeologous intermolecular gene conversion are not differentially affected by mutations in the DNA damage or the mismatch repair genes RAD1, RAD50, RAD51, RAD52, RAD54, PMS1 and MSH2
- National Institute of Environmental Health Sciences, Research Triangle Park, NC (United States); and others
Mismatch repair (MMR) genes or genes involved in both DNA damage repair and homologous recombination might affect homeologous vs. homologous recombination differentially. Spontaneous mitotic gene conversion between a chromosome and a homologous or homeologous donor sequence (14% diverged) on a single copy plasmid was examined in wild-type Saccharomyces cerevisiae strains and in MMR or DNA damage repair mutants. Homologous recombination in rad51, rad52 and rad54 mutants was considerably reduced, while there was little effect of rad1, rad50, pms1 and msh2 null mutations. DNA divergence resulted in no differential effect on recombination rates in the wild type or the mutants; there was only a five- to 10-fold reduction in homeologous relative to homologous recombination regardless of background. Since DNA divergence is known to affect recombination in some systems, we propose that differences in the role of MMR depends on the mode of recombination and/or the level of divergence. Based on analysis of the recombination breakpoints, there is a minimum of three homologous bases required at a recombination junction. A comparison of Rad{sup +} vs. rad52 strains revealed that while all conversion tracts are continuous, elimination of RAD52 leads to the appearance of a novel class of very short conversion tracts. 67 refs., 5 figs., 4 tabs.
- OSTI ID:
- 543014
- Journal Information:
- Genetics, Vol. 143, Issue 2; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Requirement of mismatch repair genes MSH2 and MSH3 in the RAD1-RAD10 pathway of mitotic recombination in Saccharomyces cerevisiae
Homologous, homeologous, and illegitimate repair of double-strand breaks during transformation of a wild-type strain and a rad52 mutant strain of Saccharomyces cerevisiae