Kearney B, Staskawicz B J
Department of Genetics, University of California, Berkeley 94720.
J Bacteriol. 1990 Jan;172(1):143-8. doi: 10.1128/jb.172.1.143-148.1990.
IS476 is an endogenous insertion sequence present in copper-tolerant strains of Xanthomonas campestris pv. vesicatoria. Sequence analysis has revealed that the element is 1,225 base pairs in length, has 26-base-pair inverted repeats, and causes a 4-base-pair target site duplication upon insertion into the avirulence gene avrBs1. Comparison of the full-length sequence with sequences in the National Biomedical Research Foundation and National Institutes of Health data bases showed that one of the predicted IS476 proteins is partially homologous to the putative transposase of IS3 from Escherichia coli, and the inverted repeats of IS476 have significant homology to the inverted repeats of the IS51 insertion sequence of Pseudomonas syringae pv. savastanoi. A transposition assay based on the insertional inactivation of the sacRB locus of Bacillus subtilis was used to demonstrate that one of the three copies of IS476 residing on the 200-kilobase copper plasmid pXVCU1 is capable of transposition in several strains of Xanthomonas campestris. The position of IS476 insertion in several avrBs1 mutants was established and was shown to influence both induction of hypersensitivity and bacterial growth in planta.
IS476是一种存在于野油菜黄单胞菌致病变种耐铜菌株中的内源性插入序列。序列分析表明，该元件长度为1225个碱基对，具有26个碱基对的反向重复序列，并且在插入无毒基因avrBs1时会导致4个碱基对的靶位点重复。将全长序列与国家生物医学研究基金会和美国国立卫生研究院数据库中的序列进行比较，结果显示预测的IS476蛋白之一与大肠杆菌IS3的推定转座酶部分同源，并且IS476的反向重复序列与丁香假单胞菌致病变种萨瓦斯坦诺IS51插入序列的反向重复序列具有显著同源性。基于枯草芽孢杆菌sacRB基因座插入失活的转座测定法被用于证明位于200千碱基铜质粒pXVCU1上的三个IS476拷贝之一能够在几种野油菜黄单胞菌菌株中进行转座。确定了IS476在几个avrBs1突变体中的插入位置，并表明其会影响过敏反应的诱导以及植物体内的细菌生长。
