A galactose-inducible HO gene was used to induce mating type switching in heterothallic Saccharomyces cerevisiae cells arrested in G1, in rad52 mutants defective in DNA damage repair, and in cells lacking the donor cassettes. The HO-cleaved MAT intermediate is stable over significant lengths of time, i.e. HO cleavage is not coupled to the subsequent gene conversion event. The in vivo cleavage site was mapped to single base resolution by primer extension experiments on total genomic DNA. Cells arrested in G1 with alpha-factor switched mating type thus demonstrating that switches can occur in the absence of replication of the genome. rad52 mutants did not produce MAT DNA of the opposite mating type indicating that the block is prior to the gene duplication stage of the switch. In strains in which the HM donor cassettes are deleted the cut MAT DNA was degraded after induction of the HO gene.

• PMID: 2558285
• PubMed
• PubTator

Reference Type

Journal Article | Research Support, U.S. Gov't, P.H.S.

Authors

Raveh D, Hughes SH, Shafer BK, Strathern JN

Primary Lit For

HO

Additional Lit For

RAD52 | HML | HMR | MATALPHA | MATA

Review For