Genetic evidence for different RAD52-dependent intrachromosomal recombination pathways in Saccharomyces cerevisiae

• Published in: Current genetics 1995-03, Vol.27 (4), p.298-305
• Main Author: Aguilera, A. (Sevilla Univ. (Spain). Facultad de Biologia. Dept. de Genetica)
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphatases; Chromosomes, Fungal - genetics; Diploidy; DNA Repair Enzymes; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Endonucleases - genetics; Endonucleases - metabolism; Fungal Proteins - genetics; Fungal Proteins - metabolism; Gene Conversion; Gene Deletion; Intrachromosomal recombination; Meiosis; Mitosis; Mitosis and meiosis; MUTACION; MUTATION; Pflanzenzuechtung; RAD10; rad51 mutations; Rad51 Recombinase; Rad52 DNA Repair and Recombination Protein; RAD52-dependent pathways; rad57 mutations; RECOMBINACION; RECOMBINAISON; Recombination, Genetic; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae - cytology; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins; Single-Strand Specific DNA and RNA Endonucleases; VARIACION GENETICA; VARIATION GENETIQUE
• ISSN: 0172-8083; 1432-0983
• DOI: 10.1007/BF00352096

Mutations in the RecA-like genes RAD51 and RAD57 reduce the frequency of gene conversion/reciprocal exchange between inverted repeats 7-fold. However, they enhance the frequency of deletions between direct repeats 5-12-fold. These induced deletions are RAD1- and RAD52-dependent. On the basis of these results it is proposed that there are several RAD52-dependent pathways of recombination: the recombinational repair pathway of gene conversion/reciprocal exchange dependent on RAD51 and RAD57; a RAD1 - and RAD52-dependent pathway exclusively responsible for deletions that are induced in rad51 and rad57 mutants; and finally, it is possible that the gene conversion/reciprocal exchange events observed in rad51 and rad57 strains represent another RAD52-dependent recombination pathway of gene conversion/reciprocal exchange that does not require Rad51 and Rad57 functions. It is also shown that the RAD10 excision-repair gene is involved in long gene conversion tracts in homologous recombination between inverted repeats, as previously observed for RAD1. Finally, an analysis of meiotic recombination reveals that deletions are induced in meiosis 100-fold above mitotic levels, similar to intrachromosomal gene conversion/reciprocal exchange, and that, in contrast to intrachromosomal meiotic gene conversion (50% association), intrachromosomal meiotic gene conversion is not preferentially associated with reciprocal exchange (12-30% of association).