Kovach M E, Shaffer M D, Peterson K M
Department of Microbiology and Immunology, Louisiana State University Medical Center, Shreveport 71130, USA.
Microbiology (Reading). 1996 Aug;142 ( Pt 8):2165-74. doi: 10.1099/13500872-142-8-2165.
A large cluster of virulence genes encoding proteins involved in Vibrio cholerae accessory colonization factor (ACF) expression and toxin-coregulated pilus (TCP) biogenesis is flanked by sequences that resemble bacteriophage attachment (att) half-sites. Adjacent to the attL-like site is a gene (int) that encodes a protein related to the integrase family of site-specific recombinases. The putative vibrio integrase appears to be most closely related to the Escherichia coli cryptic prophage (CP4-57) integrase protein (52% identity, 73% similarity). Genomic analysis of numerous V. cholerae strains (O1, non-O1 and O139) revealed that only vibrios capable of causing epidemic Asiatic cholera possess the TCP-ACF colonization gene cluster in association with the integrase. The fact that the integrase gene is absent in avirulent strains suggests that epidemic strains of V. cholerae obtained the TCP-ACF colonization gene cluster via horizontal transfer.
一大簇毒力基因编码参与霍乱弧菌辅助定植因子（ACF）表达和毒素协同菌毛（TCP）生物合成的蛋白质，其两侧是类似于噬菌体附着（att）半位点的序列。与attL样位点相邻的是一个基因（int），它编码一种与位点特异性重组酶的整合酶家族相关的蛋白质。推测的弧菌整合酶似乎与大肠杆菌隐蔽前噬菌体（CP4-57）整合酶蛋白关系最为密切（同一性为52%，相似性为73%）。对众多霍乱弧菌菌株（O1、非O1和O139）的基因组分析表明，只有能够引起流行性亚洲霍乱的弧菌才拥有与整合酶相关的TCP-ACF定植基因簇。无毒力菌株中不存在整合酶基因这一事实表明，霍乱弧菌的流行菌株是通过水平转移获得TCP-ACF定植基因簇的。
