Generation of Viable Candida albicans Mutants Lacking the “Essential” Protein Kinase Snf1 by Inducible Gene Deletion

Abstract

Essential genes are those that are indispensable for the viability and growth of an organism. Previous studies indicated that the protein kinase Snf1, a central regulator of metabolic adaptation, is essential in the pathogenic yeast Candida albicans , because no homozygous snf1 deletion mutants of C. albicans wild-type strains could be obtained by standard approaches. In order to investigate the lethal consequences of SNF1 deletion, we generated conditional mutants in which SNF1 could be deleted by forced, inducible excision from the genome. Unexpectedly, we found that snf1 null mutants were viable and could grow slowly under optimal conditions. The growth phenotypes of the snf1 Δ mutants explain why such mutants were not recovered in previous attempts. Our study demonstrates that inducible gene deletion is a powerful method for assessing gene essentiality in C. albicans .