RESUMO
OSH3 is one of the seven yeast homologues of the oxysterol binding proteins (OSBPs) which have the major binding affinity to the oxysterols and function as regulator of cholesterol biosynthesis in mammals. Mutational analysis of OSH3 showed that OSH3 plays a regulatory role in the yeast-to-hyphal transition through its oxysterol-binding domain in Saccharomyces cerevisiae. The OSH3 gene was also identified in the pathogenic yeast Candida albicans. Deletion of OSH3 caused a defect in the filamentous growth, which is the major cause of the C. albicans pathogencity. The filamentation defect of the mutation in the MAPK-associated transcription factor, namely cph1Delta was suppressed by overexpression of OSH3. These findings suggest the regulatory roles of OSH3 in the yeast filamentous growth and the functional conservations of OSH3 in S. cerevisiae and C. albicans.
Assuntos
Candida albicans/genética , Receptores de Esteroides/genética , Saccharomyces cerevisiae/genética , Candida albicans/crescimento & desenvolvimento , Proteínas Fúngicas/genética , Proteínas Fúngicas/fisiologia , Deleção de Genes , Regulação Fúngica da Expressão Gênica/genética , Modelos Genéticos , Fenótipo , Reação em Cadeia da Polimerase/métodos , Receptores de Esteroides/fisiologia , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/fisiologia , Fatores de Transcrição/genéticaRESUMO
In order to understand the biological complexity inherent to the pathogenicity of Candida albicans, gene expressions need to be analyzed at the protein level. We employed an epitope-tagging technique in a set of C. albicans ORF, and constructed fifteen strains which expressed HA-tagged proteins. These efforts permitted us to identify differentially synthesized proteins during the hyphal differentiations. ICL1, MLS1, and WAP1, all of which are known to be hypha-induced at the transcript level, were indeed found to be up-regulated at the protein level. We also identified CaeIF4G, CaTPO5, and CaZRT1, the protein levels of which were increased during hyphal transition, and CaERB1, the protein level of which was reduced consistently. The hypha-induced protein level of CaeIF4G was closely associated with the cellular hyphal phenotype. CaeIF4G overexpression was shown to result in hyperfilamentation in C. albicans. CaeIF4E, which was constitutively expressed during the hyphal development, exhibited no overexpression phenotype. HA-tagged strains were also utilized in our analysis of C. albicans proteins in a co-culture of macrophage and C. albicans. Five genes were found to be expressed differentially during the macrophage co-cultures. Our approaches proved to be rather useful under yeast culture conditions as well as in co-cultures of macrophage and C. albicans.