DISSEMINATION OF BACTERIAL ENTEROTOXIN GENES

我们已经从猪中克隆了耐热肠毒素STII的基因， 大肠杆菌菌株coli中表达，并测定了其DNA序列。 初步数据 提示人源E.大肠杆菌、沙门氏菌和志贺氏菌也 含有STII基因。 STII基因在E.大肠杆菌位于 反向重复序列，这表明它与一个 转座因子 STII基因的转座性将是 确定并检查插入部位的性质。 的 STII转座子的大小和转座所必需的序列 将被确定。 由于末端反向重复区的边界 STII基因很大，这些区域的可能性， 转座子本身将被研究。 的转座性 STII基因在其它E.大肠杆菌分离株进行检测。 if转置 发生，那么转座因子的结构将是 测定 最后，我们将开展类似的研究，以确定 STII基因在其他肠源性大肠杆菌中的存在和结构 细菌 然后将检测其他细菌中存在的STII基因 转座性 以这种方式，关于分子的信息 本文对E.杆菌 获得细菌间的STII基因。

We have cloned the gene for the heat-stable enterotoxin STII from a porcine strain of E. coli and determined its DNA sequence. Preliminary data suggest that human isolates of E. coli, Salmonella, and Shigella also contain this STII gene. The STII gene in E. coli is located between two inverted repeat sequences, suggesting that it is associated with a transposable element. The transposability of the STII gene willl be determined and the nature of the insertion sites will be examined. The size of the STII transposon and the sequences essential for transposition will be ascertained. Since the terminal inverted repeat regions bordering the STII gene are large, the possibility that these regions are, themselves, transposons will be investigated. The transposability of the STII gene in other E. coli isolates will be examined. If transposition occurs, then the structure of the transposable elements will be determined. Finally, we will initiate similar studies to determine the presence and structure of STII gene in other species of enterotoxigenic bacteria. The STII genes present in other bacteria will then be assayed for transposability. In this manner, information concerning the molecular nature, the mechanism of dissemination, and the distribution of the E. coli STII gene among bacterial will be obtained.