Analysis of base excision and nucleotide excision repair in Candida albicans

Candida albicans, clinically the most important human fungal pathogen, rapidly develops resistance to antifungal drugs. The acquisition of resistance has been linked to various types of genome changes. As part of an ongoing study of this problem, we investigated mutation, genome stability and drug resistance acquisition in C. albicans strains with deletions in the base excision repair (BER) genes NTG1, APN1 and OGG1, and in the nucleotide excision repair (NER) genes RAD2 and RAD10. The BER mutants did not exhibit any change in their susceptibility to DNA-damaging agents, but the NER mutants were extremely sensitive to UV-induced DNA damage. We did not observe any significant change in mutation, genome stability and antifungal drug sensitivity in the mutant strains we tested. However, we detected a number of intriguing phenotypic differences between strains bearing deletions in equivalent C. albicans and Saccharomyces cerevisiae BER and NER genes, which may be related to differences in the life cycles of these two fungi.