The RAD52 ortholog of Yarrowia lipolytica is essential for nuclear integrity and DNA repair.

Yarrowia lipolytica (Yl) is a dimorphic fungus that has become a well-established model for a number of biological processes, including secretion of heterologous and chimerical proteins. However, little is known on the recombination machinery responsible for the integration in the genome of the exogenous DNA encoding for those proteins. We have carried out a phenotypic analysis of rad52 deletants of Y. lipolytica. YlRad52 exhibited 20-30% identity with Rad52 homologues of other eukaryotes, including Saccharomyces cerevisiae and Candida albicans. Ylrad52-Δ strains formed colonies on YPD-agar plates which were spinier and smaller than those from wild type, whereas in YPD liquid cultures they exhibited a decreased grow rate and contained cells with aberrant morphology and fragmented chromatin, supporting a role for homologous recombination (HR) in genome stability under nondamaging conditions. In addition, Ylrad52 mutants showed moderate to high sensitivity to UV light, oxidizing agents and compounds that cause single- (SSB) and double-strand breaks (DSB), indicating an important role for Rad52 in DNA repair. These findings extend to Yl previous observations indicating that RAD52 is a crucial gene for DNA repair in other fungi, including S. cerevisiae, C. albicans and Schizosaccharomyces pombe.