CTX genetic element encodes a site-specific recombination system and an intestinal colonization factor.
CTX genetic element encodes a site-specific recombination system and an intestinal colonization factor.
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DOI：
10.1073/pnas.90.8.3750
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发表时间：
1993-04
影响因子：
11.1
通讯作者：
G. D. Pearson;A. Woods;S. L. Chiang;J. Mekalanos
中科院分区：
文献类型：
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作者：
G. D. Pearson;A. Woods;S. L. Chiang;J. Mekalanos
在霍乱弧菌中，编码霍乱毒素(CtxAB)的基因位于DNA的一段(称为“核心”区)上，其两侧是一个称为RS1的重复序列的两个或多个副本。这些DNA单位共同构成了CTX基因元件。本文提供的证据表明，RS1序列编码一个位点特异性的重组系统，该系统允许携带RS1的自杀质粒整合到位于非产毒霍乱弧菌染色体上的18个碱基对的序列(AttRS1)中。缺失attRS1和整个CTX基因元件的霍乱弧菌菌株不再与RS1序列进行定点重组。此外，这些缺失菌株在肠道定植方面存在缺陷。重组实验将负责促进定植的基因定位到CTX元件核心区的一部分。已鉴定的基因编码一种氨基酸序列与嗜水气单胞菌柔性菌毛蛋白高度相似的多肽。这些结果对构建稳定的减毒活霍乱疫苗具有重要意义。
In Vibrio cholerae, the genes encoding cholera toxin (ctxAB) are located on a segment of DNA (termed the "core" region) that is flanked by two or more copies of a repeated sequence called RS1. Together these DNA units comprise the CTX genetic element. Evidence presented here suggests that RS1 sequences encode a site-specific recombination system, which allows integration of a suicide plasmid carrying RS1 into an 18-base-pair sequence (attRS1) located on the chromosome of nontoxigenic V. cholerae strains. Strains of V. cholerae with large deletions removing attRS1 and the entire CTX genetic element no longer undergo site-specific recombination with the RS1 sequence. Additionally, these deletion strains show a defect in intestinal colonization. Recombination experiments localize the gene responsible for enhancing colonization to a portion of the core region of the CTX element. The identified gene encodes a peptide that is highly similar in amino acid sequence to the flexible pilin of Aeromonas hydrophila. These results have important implications in the construction of stable, live attenuated cholera vaccines.