Colonization factor and protective antigen of Vibrio cholerae O1

为鉴定霍乱弧菌对肠上皮的黏附因子，研究了V14菌毛（黏附物）与霍乱弧菌的关系。虽然V14菌毛未在霍乱弧菌表面表达，但在细胞质中检测到其抗原。主要亚基pilin （vcfA，或霍乱弧菌中的mshA）的基因分析从蛋白的n端氨基酸序列开始。vcfA的n端序列与mshA高度同源，而c端序列是独立的。由于Δ vcfA菌株对Hep2细胞具有相同的粘附性，因此对V14菌毛的整个结构操纵子进行了研究。结果表明，霍乱弧菌O34株的MSHA菌毛和V14菌毛的基因簇有7个orf，除了MSHA的c端序列和mshQ的n端序列外，两者之间的orf几乎相同，而且该菌毛由3个亚基蛋白组成（1个主菌毛蛋白和2个次菌毛蛋白），mshQ编码负责菌毛生物发生的外膜蛋白。从这些结果来看，V14菌毛被认为是霍乱弧菌O1的MSHA菌毛的变体，并且不参与粘附。

To identify adhesive factor of Vibrio cholerae to the intestinal epithelium, the relation between V14 pili (adhesive) and cholera vibrios were investigated. Although V14 pilus was not expressed on the surface of cholera vibrios, its antigen was detected in the cytoplasm. The gene analysis of major subunit pilin (vcfA, or mshA in cholera vibrio) started from the N-terminal amino acid sequence of the protein. N-terminal sequence of vcfA was highly homologous to mshA, but the C-terminal sequence was independent. Since Δ vcfA strain was equally adhesive to Hep2 cells, whole structural operon of V14 pilus was investigated. After all, it was clarified that the gene clusters of MSHA pili and V14 pili of a V. cholerae O34 strain had 7 ORFs, and that the ORFs were almost identical between the two, except C-terminal sequence of mshA and N-terminal of mshQ, and that the pili consisted of 3 subunit proteins (a major pilin and 2 minor pilins), and that mshQ encodes outer membrane protein which is responsible for the biogenesis of pili. From these results, V14 pilus was regarded as a variant of MSHA pilus of V. cholerae O1, and is not involved in adhesion.