Characterization of genes regulating dimorphic transition between yeast and pseudohyphal form.

乙醇对热带假丝酵母Pk233的菌丝生长有促进作用。乙醇培养呈现双相生长曲线。在乙醇培养的第一个生长阶段，膨胀的球形酵母细胞积累，进入第二阶段后，出现假菌丝细胞，从膨胀的酵母细胞中伸出。对乙醇培养的cDNA进行消减克隆，用杂交的方法从对照培养的cDNA中减去。分离的菌株包括编码硫胺素生物合成酶的Ctnmt1^+和编码酪氨酸磷酸酶的白色念珠菌CPP1的同源物Ctnmt1^+。乙醇诱导的假菌丝形成过程与硫胺素代谢有关，因为在第一生长阶段后期添加外源硫胺素抑制了假菌丝生长的伸长。CtPP1的破坏导致了假菌丝形成的表型缺陷，提示MAP激酶级联参与了假菌丝的形成。

Ethanol caused mycelial growth in the imperfect yeast Candida tropicalis Pk233. Cultivation with ethanol gave biphasic growth curves. During the first growth phase in the ethanol culture, there was an accumulation of swollen spherical yeast cells and after entering the second phase, pseudohyphal cells appeared, projecting from the swollen yeast cells. Subtractive cloning of genes was performed on the cDNAs of the ethanol culture, from which the cDNAs of the control cultur had been subtracted by hybridization. Isolated included Ctnmt1^+ homologous to S.pombe nmt1^+ oncoding the enzyme for thiamine biosynthesis and CtPP1 homologous to C.albicans CPP1 encoding tyrosine phosphatase.. Correlation was suggested of the process of ethanol-induced pseudomycelial formation with thiamine metabolism, since the elongation of the pseudohyphal growth was suppressed when exogenous thiamine was supplemented at the late stage of the first growth phase. Disruption of CtPP1 brought about the phenotype defective in pseudomycelial formation, suggesting the participation of MAP kinase cascade in the formation.