Gale CA, Berman J; American Society for Microbiology. General Meeting.

Abstr Gen Meet Am Soc Microbiol. 1998 May 17-21; 98: 363 (abstract no. M-9).

Univ. of MN, St. Paul, USA.

Adhesion to epithelial cells, filamentous growth, and virulence of Candida albicans are all linked via a single gene, INT1. Over-expression of C. albicans INT1 in Saccharomyces cerevisiae is sufficient to allow this yeast to adhere to human epithelial cells and to undergo a morphologic switch to filamentous forms similar to C. albicans germ tubes. We seek to understand the function of INT1 in C. albicans morphogenesis by using S. cerevisiae as a model system in which to disect the mechanism of Int1p-induced filamentous growth. C. albicans Int1p and S. cerevisiae Bud4p share approximately 35% identity in their C-terminal 300 amino acids. Despite this, Bud4p overexpression does not mimic the Int1p-induced filamentous phenotype. In addition, Int1p-induced filamentous growth occurs in a bud4 strain, suggesting that BUD4 is not a functional homolog of INT1 and that BUD4 is not required for the INT1 phenotype. Phalloidin staining of S. cerevisiae expressing INT1 shows that the actin in Int1p-induced filaments is hyperpolarized. Pre-treatment of INT1-expressing cells with alpha-factor or mutation of cdc24 suppresses Int1p-induced filamentous growth, suggesting that the yeast cell must be committed to bud formation to respond to INT1. In addition, there is abnormal localization of a GFP-tagged septin (GFP-Sep7p) in S. cerevisiae cells expressing INT1. DAPI staining shows that the nuclei in Int1p-induced haploid cells usually contain a 2N amount of DNA, suggesting that yeast cells expressing INT1 are delayed in G2. Interestingly, Int1p-induced filamentous growth is suppressed by alterations in the levels of Clb2p, a B-type cyclin. In summary, INT1 expression causes changes in cell morphology at least in part by interacting with structural components of the bud neck, with the cytoskeleton, and with cell cycle regulators.

Publication Types:

• Meeting Abstracts

Keywords:

• Actins
• Antigens, Fungal
• Candida albicans
• Cell Cycle
• Cell Cycle Proteins
• Cyclins
• Humans
• Mutation
• Saccharomyces cerevisiae
• Saccharomyces cerevisiae Proteins
• Virulence
• genetics
• immunology

Other ID:

• 98296596

UI: 102226560

From Meeting Abstracts