Characterization of two putative Candida albicans zinc finger transcription factors possibly involved in regulating cell wall function.
Tobias Schwarzmueller (1), Alisina Sarabi (1), Steffen Rupp (2), Karl Kuchler (1)
(1) Medical Biochemistry, Medical University of Vienna, Dr. Bohr Gasse 9/2, Wien, 1030, Austria; (2) Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB, Nobelstraße 12, D-70569 Stuttgart, Germany
The cell wall and associated surface proteins are essential for adhesion and invasion of immune cells by fungal pathogens. Because expression of many cell surface proteins depend upon the state of infection and the fungal morphology, their expression regulation is likely to require transcription factors activated by distinct signals from the outside or the host. In the diploid yeast C.albicans several cell wall proteins have been connected to virulence. However, little is known about the expression under different physiological conditions or during host invasion. We study several transcription factors that show a structural similarity to well-characterized S. cerevisiae TF. Homologous C. albicans genes were deleted using auxotrophic markers and deletion strains were confirmed by PCR and Southern analysis. Two homozygous deletions strains were obtained and named Δ zcp6 and Δ zcp7. Their phenotype under different growth conditions was analyzed. One strain, Δ zcp6, displayed increased sensitivity to ionic detergents such as SDS, cell wall-damaging agents, as well as severe defects in filamentation on hyphae-inducing media. A second strain, Δ zcp7, showed an increased resistance to the lytic enzyme zymolyase. These data imply that both putative TF may control expression of genes affecting the cell wall function. Hence, these regulators might play an important role in the pathogenicity of C. albicans. Currently we characterize these regulators.