Kandasamy R, Vediyappan G, Chaffin W L
Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
FEMS Microbiol Lett. 2000 May 15;186(2):239-43. doi: 10.1111/j.1574-6968.2000.tb09111.x.
Pir proteins are unique proteins with internal repeat sequences that are reported to be present in the cell wall of Saccharomyces cerevisiae. They are covalently attached to the cell wall and can be released by mild alkali treatment. In this study the biotinylated cell wall preparations from Candida albicans and S. cerevisiae were extracted by alkali and beta-1,3 glucanase and analyzed in parallel. Among the four bands detected by streptavidin, two proteins were recognized by the antibody to the S. cerevisiae Pir protein Hsp150. The antibody also detected a high molecular mass protein secreted in the growth medium of C. albicans. Using S. cerevisiae HSP150/PIR2 gene as a probe, Southern and Northern hybridizations were performed with DNA and RNA of C. albicans. Hybridization with DNA digested with different restriction enzymes showed more than one hybridized fragment. An increased level of mRNA was found in heat shocked cells (37 degrees C for 45 min compared to 25 degrees C). Hybridization of ScHSP150 gene to mRNAs from cells grown in different media was also determined. Two transcripts of size approximately 3.5 kb and 2.0 kb were detected in mRNAs from cells grown in defined medium with glucose as carbon source or in the same medium supplemented with hemoglobin. The lower transcript of size 2.0 kb was absent in cells grown in medium with galactose as carbon source. A single band was also observed when cells were grown in rich medium. Together these results demonstrated the existence of beta1,3 glucan linked proteins in C. albicans, which are related to Pir family proteins of S. cerevisiae.
Pir蛋白是具有内部重复序列的独特蛋白质，据报道存在于酿酒酵母的细胞壁中。它们共价连接到细胞壁上，可通过温和的碱处理释放出来。在本研究中，白色念珠菌和酿酒酵母的生物素化细胞壁制剂用碱和β-1,3葡聚糖酶提取并进行平行分析。在链霉亲和素检测到的四条带中，有两种蛋白质被酿酒酵母Pir蛋白Hsp150的抗体识别。该抗体还检测到白色念珠菌生长培养基中分泌的一种高分子量蛋白质。以酿酒酵母HSP150/PIR2基因作为探针，对白色念珠菌的DNA和RNA进行Southern和Northern杂交。用不同限制酶消化的DNA杂交显示有多个杂交片段。在热休克细胞中发现mRNA水平升高（与25℃相比，37℃处理45分钟）。还测定了ScHSP150基因与在不同培养基中生长的细胞的mRNA的杂交情况。在以葡萄糖为碳源的限定培养基中生长的细胞或添加血红蛋白的相同培养基中生长的细胞的mRNA中检测到大小约为3.5 kb和2.0 kb的两种转录本。在以半乳糖为碳源的培养基中生长的细胞中不存在大小为2.0 kb的较低转录本。当细胞在丰富培养基中生长时也观察到一条带。这些结果共同证明了白色念珠菌中存在与酿酒酵母Pir家族蛋白相关的β1,3葡聚糖连接蛋白。
