The adhesin Hwp1 and the first daughter cell localize to the a/a portion of the conjugation bridge during Candida albicans mating

• Published in: Molecular biology of the cell 2003-12, Vol.14 (12), p.4920-4930
• Main Authors: Daniels, Karla J, Lockhart, Shawn R, Staab, Janet F, Sundstrom, Paula, Soll, David R
• Format: Article
• Language: English
• Subjects: Blotting, Northern; Candida albicans - cytology; Candida albicans - genetics; Candida albicans - metabolism; Cell Adhesion - physiology; Cell Wall - genetics; Cell Wall - metabolism; Fluorescent Antibody Technique; Fungal Proteins - genetics; Fungal Proteins - metabolism; Genes, Fungal - genetics; Genes, Mating Type, Fungal; Hyphae - cytology; Hyphae - genetics; Hyphae - metabolism; Mating Factor; Membrane Glycoproteins - genetics; Membrane Glycoproteins - metabolism; Models, Molecular; Peptides - metabolism; Transcriptional Activation; Zygote - metabolism
• ISSN: 1059-1524; 1939-4586
• DOI: 10.1091/mbc.E03-04-0264

The cell wall protein Hwp1 was originally demonstrated to be expressed exclusively in hyphae of Candida albicans and cross-linked to human epithelium by mammalian transglutaminase. Hwp1 is expressed on the walls of hyphae formed by a/alpha, a/a, and alpha/alpha cells. Hence, it is expressed on hyphae independently of mating type. However, Hwp1 is selectively expressed on the wall of conjugation tubes formed by a/a cells, but not alpha/alpha cells, in the mating process. This was demonstrated in all possible crosses between four unrelated natural a/a strains and four unrelated alpha/alpha strains. In zygotes, Hwp1 is restricted to that portion of the wall of the conjugation bridge contributed by the a/a parent cell. Hwp1 staining further revealed that the first daughter bud that emerges from the conjugation bridge does so from the a/a-contributed portion. Hwp1 expression and localization during the mating process is, therefore, mating type specific, opaque phase specific, and alpha-pheromone induced. These results indicate that the mating type-specific contributions to the conjugation bridge during the mating process in C. albicans are qualitatively and functionally distinct and that the a/a portion of the bridge, which selectively contains Hwp1, bears the first daughter cell in the mating process.