The Phenotypic Consequences of the White-Opaque Transition in Candida Albicans: The Cell Wall and Gene Regulation

Abstract

There are two levels of phenotypic variability in the dimorphic yeast Candida albicans and both impact on the cell wall. The basic level includes the bud-hypha transition. Cells growing in the budding form can generate a narrow, elongate germ tube which continues to grow as a compartmentalized, sometimes branching tube. All normal cells are capable of converting between the two growth forms, and under experimental conditions, rapid mass conversion from one form to the other can be induced (Odds, 1988; Buffo et al.,1984; Simonetti et al.,1974). The bud-hypha transition has been considered a developmental process involving both differential gene expression (Finney et al., 1985; Maiming and Mitchell, 1980) and the differential utilization of common cell cycle functions (Soll, 1986; Soll and Mitchell, 1983). As in most cases in which rapid and reversible differentiation of an entire cell population can be induced, it is assumed that the molecular mechanisms involved in regulation include environmentally induced gene activation and deactivation in regulatory cascades, and reorganizations of metabolism and subcellular architecture (Soll, 1986), but usually no reorganization of the basic genetic material.