Mutations in XRS2 and RAD50 delay but do not prevent mating-type switching in Saccharomyces cerevisiae - PubMed (original) (raw)

Mutations in XRS2 and RAD50 delay but do not prevent mating-type switching in Saccharomyces cerevisiae

E L Ivanov et al. Mol Cell Biol. 1994 May.

Abstract

In Saccharomyces cerevisiae, a large number of genes in the RAD52 epistasis group has been implicated in the repair of chromosomal double-strand breaks and in both mitotic and meiotic homologous recombination. While most of these genes are essential for yeast mating-type (MAT) gene switching, neither RAD50 nor XRS2 is required to complete this specialized mitotic gene conversion process. Using a galactose-inducible HO endonuclease gene to initiate MAT switching, we have examined the effect of null mutations of RAD50 and of XRS2 on intermediate steps of this recombination event. Both rad50 and xrs2 mutants exhibit a marked delay in the completion of switching. Both mutations reduce the extent of 5'-to-3' degradation from the end of the HO-created double-strand break. The steps of initial strand invasion and new DNA synthesis are delayed by approximately 30 min in mutant cells. However, later events are still further delayed, suggesting that XRS2 and RAD50 affect more than one step in the process. In the rad50 xrs2 double mutant, the completion of MAT switching is delayed more than in either single mutant, without reducing the overall efficiency of the process. The XRS2 gene encodes an 854-amino-acid protein with no obvious similarity to the Rad50 protein or to any other protein in the database. Overexpression of RAD50 does not complement the defects in xrs2 or vice versa.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Nature. 1981 Jul 23;292(5821):306-11 - PubMed
    1. Mol Cell Biol. 1990 Aug;10(8):3859-67 - PubMed
    1. Mol Cell Biol. 1981 Jun;1(6):522-34 - PubMed
    1. Proc Natl Acad Sci U S A. 1986 Oct;83(20):7831-5 - PubMed
    1. Nucleic Acids Res. 1987 Feb 11;15(3):1281-95 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources