Intrachromosomal Recombination in Saccharomyces cerevisiae : Reciprocal Exchange in an Inverted Repeat and Associated Gene Conversion

Kerry K. Willis ¹ and Hannah L. Klein ¹

¹ Department of Biochemistry, New York University, New York, New York 10016

Intrachromosomal gene conversion has not shown a strong association with reciprocal exchanges. However, reciprocal exchanges do occur between intrachromosomal repeats. To understand the relationship between reciprocal exchange and gene conversion in repeated sequences the recombination behavior of an inverted repeat was studied. We have found that in one orientation a single copy of the kan^r gene of the bacterial transposon Tn903 flanked by part of the inverted repeats IS903 does not give G418 resistance in Saccharomyces cerevisiae. A reciprocal exchange in the IS903 repeats inverts the kan ^r gene, which then gives G418 resistance in a single copy. Using this as a selection for intrachromosomal reciprocal exchange we have introduced multiple restriction site heterologies into the IS903 repeats and examined the crossover products for associated gene conversions. Approximately 50% of crossovers, both in mitosis and meiosis, were associated with a gene conversion. This suggests that these crossovers result from an intermediate that gives a gene conversion in 50% of the events, that is, both reciprocal exchange and gene conversion between repeated sequences have a common origin. The data are most consistent with a heteroduplex mismatch repair mechanism.

This article has been cited by other articles:

				L. S. Symington Role of RAD52 Epistasis Group Genes in Homologous Recombination and Double-Strand Break Repair Microbiol. Mol. Biol. Rev., December 1, 2002; 66(4): 630 - 670. [Abstract] [Full Text] [PDF]

				P. J. E. Quintana, E. A. H. Neuwirth, and A. J. Grosovsky Interchromosomal Gene Conversion at an Endogenous Human Cell Locus Genetics, June 1, 2001; 158(2): 757 - 767. [Abstract] [Full Text] [PDF]

				Y. Bai, A. P. Davis, and L. S. Symington A Novel Allele of RAD52 That Causes Severe DNA Repair and Recombination Deficiencies Only in the Absence of RAD51 or RAD59 Genetics, November 1, 1999; 153(3): 1117 - 1130. [Abstract] [Full Text]

				F. Paques and J. E. Haber Multiple Pathways of Recombination Induced by Double-Strand Breaks in Saccharomyces cerevisiae Microbiol. Mol. Biol. Rev., June 1, 1999; 63(2): 349 - 404. [Abstract] [Full Text] [PDF]

				W. Chen and S. Jinks-Robertson Mismatch Repair Proteins Regulate Heteroduplex Formation during Mitotic Recombination in Yeast Mol. Cell. Biol., November 1, 1998; 18(11): 6525 - 6537. [Abstract] [Full Text]

				Evidence for Independent Mismatch Repair Processing on Opposite Sides of a Double-Strand Break in Saccharomyces cerevisiae Genetics, January 1, 1998; 148(1): 59 - 70.

				Y Bai and L S Symington A Rad52 homolog is required for RAD51-independent mitotic recombination in Saccharomyces cerevisiae. Genes & Dev., August 15, 1996; 10(16): 2025 - 2037. [Abstract] [PDF]