Miyasaki S H, White T C, Agabian N
Department of Pharmaceutical Chemistry, University of California at San Francisco 94118.
J Bacteriol. 1994 Mar;176(6):1702-10. doi: 10.1128/jb.176.6.1702-1710.1994.
Candida albicans secreted aspartyl proteinases (Sap), products of the SAP genes, which are presumed to act as virulence factors. In the C. albicans strain WO-1, the ability to secrete Sap1 is regulated with switch phenotype, another putative virulence factor. KpnI restriction fragment length polymorphisms differentiate between several distinct SAP1 alleles in laboratory and clinical strains. Both SAP1 alleles from strain WO-1 along with their 5'- and 3'-flanking regions were cloned and sequenced, as were both alleles from another strain, SS. The 5'-flanking regions were remarkably similar in all four of the sequenced alleles over approximately 1,500 nucleotides. S1 analysis revealed that both alleles of WO-1 are transcribed. Characterization of the one allele from strain WO-1 identified a 284-nucleotide insertion flanked by 8-bp direct repeats that shows homology to the CARE2 repetitive element and that is not present in the other alleles. Characterization of the SAP1 alleles also identified a fourth SAP gene (SAP4) that includes an extended leader sequence. SAP4 is positioned upstream, in tandem to SAP1, in all strains tested and may encode another closely related secreted aspartyl proteinase.
白色念珠菌分泌天冬氨酸蛋白酶（Sap），它是SAP基因的产物，被认为是毒力因子。在白色念珠菌WO-1菌株中，Sap1的分泌能力受开关表型调控，开关表型是另一种假定的毒力因子。KpnI限制性片段长度多态性可区分实验室菌株和临床菌株中几个不同的SAP1等位基因。克隆并测序了来自WO-1菌株的两个SAP1等位基因及其5'和3'侧翼区域，另一个菌株SS的两个等位基因也进行了克隆和测序。在大约1500个核苷酸的范围内，所有四个测序等位基因的5'侧翼区域非常相似。S1分析表明WO-1的两个等位基因都被转录。对来自WO-1菌株的一个等位基因的表征发现，有一个284个核苷酸的插入片段，两侧是8个碱基对的直接重复序列，该序列与CARE2重复元件具有同源性，且在其他等位基因中不存在。对SAP1等位基因的表征还鉴定出了第四个SAP基因（SAP4），它包含一个延长的前导序列。在所有测试菌株中，SAP4位于SAP1的上游，呈串联排列，可能编码另一种密切相关的分泌天冬氨酸蛋白酶。
