Zhou Z, Cao F, Chen J Y
State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, Shanghai 200031, China.
Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai). 2002 May;34(3):298-304.
Candida albicans is the most frequently isolated fungal pathogen in humans. Many factors are involved in its morphological transition. Flo8 plays an important role in morphogenesis of Saccharomyces cerevisiae. In this work, a C.albicans genomic DNA library was introduced into an S.cerevisiae flo8/flo8 mutant to screen genes which could complement its invasive growth defect. In this screening, a novel gene was isolated and designated CaSRB9 (Candida albicans SRB9 gene). The CaSRB9 gene had an ORF of 4 998 bp, encoding a putative protein of 1 665 amino acids. The CaSrb9 shared highest similarity in amino acids (38%) with Srb9 of S.cerevisiae. Ectopic expression of the CaSRB9 gene in diploid S. cerevisiae suppressed defect in filamentous growth of some mutants in filamentation MAPK pathway (ste7/ste7, ste 12 / ste 12, and tec 1 / tec 1) and flo 8 / flo 8 mutant under nitrogen starvation conditions. In haploid S. cerevisiae, ectopic expressed CaSrb9 complemented the invasive growth defect of flo8 mutant but failed to complement the invasive growth defects of the mutants in filamentation MAPK pathway.
白色念珠菌是人类中最常分离出的真菌病原体。其形态转变涉及许多因素。Flo8在酿酒酵母的形态发生中起重要作用。在这项研究中，将白色念珠菌基因组DNA文库导入酿酒酵母flo8/flo8突变体中，以筛选能够弥补其侵袭性生长缺陷的基因。在此筛选过程中，分离出一个新基因并命名为CaSRB9（白色念珠菌SRB9基因）。CaSRB9基因的开放阅读框为4998 bp，编码一个推定的含1665个氨基酸的蛋白质。CaSrb9与酿酒酵母的Srb9在氨基酸水平上具有最高的相似性（38%）。在氮饥饿条件下，CaSRB9基因在二倍体酿酒酵母中的异位表达抑制了丝状生长MAPK途径中一些突变体（ste7/ste7、ste12/ste12和tec1/tec1）以及flo8/flo8突变体的丝状生长缺陷。在单倍体酿酒酵母中，异位表达的CaSrb9弥补了flo8突变体的侵袭性生长缺陷，但未能弥补丝状生长MAPK途径中突变体的侵袭性生长缺陷。
