白念珠菌CaCdc37的表达及功能分析

Expression and Functional Analysis of Candida albicans Cdc37

CDC37基因编码的产物是一个参与蛋白激酶折叠成熟的分子伴侣蛋白,存在于多种真核生物中。在利用酵母双杂交系统筛选白念珠菌蛋白激酶Crk1相互作用蛋白时,获得一个CDC37同源基因。该基因编码区全长1524bp,编码一含508个氨基酸的蛋白质。其氨基酸序列与酿酒酵母Cdc37蛋白的序列同源性达41%。该基因在酿酒酵母中的表达能回复cdc37-1突变株的温度敏感表型,表明它能互补ScCDC37的功能。该基因命名为CaCDC37。Northern杂交显示,该基因在白念珠菌中呈组成型表达,转录水平不受形态转变和生长条件的影响;在crk1缺失株和CRK1高表达菌株中或者在cph1efg1双缺失株中,CaCDC37基因的转录水平没有明显变化。利用酵母双杂交系统分析CaCdc37与另外两个预测的白念珠菌分子伴侣蛋白CaSti1和CaHsp90的相互作用,结果表明CaCdc37能与CaSti1相互作用,而与CaHsp90的相互作用未能检测到。根据这些结果推测了CaCdc37可能的作用机制。

Cdc37 is suggested to act as a molecular chaperone which specifically involved in maturation of protein kinases. A clone containing a CDC37 orthologue was isolated from two hybrid screening with Crkl kinase domain as a bait. Open reading frame of the gene is 1 524 bp in length and encodes for a protein of 508 amino acids. The deduced amino acid sequence shares the highest similarity with S. cerevisiae Cdc37 （41% identity）. Based on the amino acid sequence similarity, the gene from C. albicans was designated CaCDC37. Northern blot analysis showed that the CaCDC37 was constitutively expressed in C. albicans. Transcriptional level of the CaCDC37 was not regulated in different morphological forms and growth conditions. It is also not affected by deletion or overexpression of the Crkl. Ectopic expression of the CaCDC37 could complement a cdc37 thermosensitive mutant （cdc37-1） of S. cerevisiae indicated that the CaCdc37 has a similar function of the ScCdc37. Yeast two hybrid assay was used to analyse interactions between the CaCdc37 and other two putative chaperons CaHsp90 and CaStil. The result showed that the CaCdc37 could interact with CaStil but not the CaHsp90.