Isolation from Candida albicans of a functional homolog of the Saccharomyces cerevisiae KRE1 gene, which is involved in cell wall beta-glucan synthesis

Abstract

The KRE1 gene of Saccharomyces cerevisiae, sacKRE1, appears to be involved in the synthesis of cell wall beta-glucan. S. cerevisiae strains with mutations in the KRE1 gene produce a structurally altered cell wall (1----6)-beta-glucan, which results in resistance to K1 killer toxin. We isolated the canKRE1 gene from Candida albicans by its ability to complement a kre1 mutation in S. cerevisiae and confer sensitivity to killer toxin. Sequence analysis revealed that the predicted protein encoded by canKRE1 shares an overall structural similarity with that encoded by sacKRE1. The canKRE1 protein is composed of an N-terminal signal sequence, a central domain of 46% identity with the sacKRE1 protein, and a C-terminal hydrophobic tract. These structural and functional similarities imply that the canKRE1 gene carries out a function in C. albicans cell wall assembly similar to that observed for sacKRE1 in S. cerevisiae.