GSBS Student Publications

Title

Mismatch correction acts as a barrier to homeologous recombination in Saccharomyces cerevisiae

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Biochemistry and Molecular Biology

Date

3-1-1995

Document Type

Article

Medical Subject Headings

Base Sequence; Chromosomes; DNA Repair; DNA-Binding Proteins; Gene Deletion; Mitosis; Molecular Sequence Data; Mutation; Recombination, Genetic; Saccharomyces cerevisiae; Sequence Homology, Nucleic Acid; TATA-Box Binding Protein; Transcription Factors

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

A homeologous mitotic recombination assay was used to test the role of Saccharomyces cerevisiae mismatch repair genes PMS1, MSH2 and MSH3 on recombination fidelity. A homeologous gene pair consisting of S. cerevisiae SPT15 and its S. pombe homolog were present as a direct repeat on chromosome V, with the exogenous S. pombe sequences inserted either upstream or downstream of the endogenous S. cerevisiae gene. Each gene carried a different inactivating mutation, rendering the starting strain Spt15-. Recombinants that regenerated SPT15 function were scored after nonselective growth of the cells. In strains wild type for mismatch repair, homeologous recombination was depressed 150- to 180-fold relative to homologous controls, indicating that recombination between diverged sequences is inhibited. In one orientation of the homeologous gene pair, msh2 or msh3 mutations resulted in 17- and 9.6-fold elevations in recombination and the msh2 msh3 double mutant exhibited an 43-fold increase, implying that each MSH gene can function independently in trans to prevent homeologous recombination. Homologous recombination was not significantly affected by the msh mutations. In the other orientation, only msh2 strains were elevated (12-fold) for homeologous recombination. A mutation in MSH3 did not affect the rate of recombination in this orientation. Surprisingly, a pms1 deletion mutant did not exhibit elevated homeologous recombination.

Rights and Permissions

Citation: Genetics. 1995 Mar;139(3):1175-88.

Related Resources

Link to Article in PubMed

Journal Title

Genetics

PubMed ID

7768431