Transduction analysis of transposon Tn551 insertions in the trp-thy region of the Staphylococcus aureus chromosome
Transduction analysis of transposon Tn551 insertions in the trp-thy region of the Staphylococcus aureus chromosome
复制标题
金黄色葡萄球菌染色体 trp-thy 区域转座子 Tn551 插入的转导分析
作者：
C. Schroeder;P. Pattee
以前的研究表明，Tn 551，一个5.2-糖苷酶对转座子，决定了红霉素的组成性耐药性，可以占据各种染色体位点之间的thy-101和trp-103的金黄色葡萄球菌8325。虽然这些插入中有许多是“沉默的”，但其他许多插入，包括赖氨酸、苏氨酸、蛋氨酸、酪氨酸和色氨酸，导致营养缺陷型突变。该区域中插入的紧密接近和红霉素抗性表型使得通过转化进行其作图变得困难。这些网站和类似的化学诱导突变的一般转导与噬菌体80 α的分析已经确定了这些插入位点的顺序和关系，并提供了一个详细的地图，该区域的染色体，包括色氨酸操纵子的方向。本研究的结果和突变体的有限表型表征表明，从天冬氨酸到赖氨酸，苏氨酸和甲硫氨酸的发散途径，酪氨酸生物合成中的几个反应，以及整个色氨酸操纵子都是由染色体的这个区域决定的。通过转导获得的连锁结果已经与以前通过转化获得的类似数据进行了比较;这种比较表明存在，在thy和lys之间，优选的用于从宿主染色体转导噬菌体DNA形态发生的满头切割位点。
Previous studies have shown that Tn551, a 5.2-kilobase-pair transposon that determines constitutive resistance to erythromycin, can occupy a variety of chromosomal sites between thy-101 and trp-103 in Staphylococcus aureus 8325. Although many of these insertions were "silent," many others, including lys, thr, met, tyr, and trp, resulted in auxotrophic mutations. The close proximity and erythromycin-resistant phenotypes of the insertions in this region have made their mapping by transformation difficult. Analysis of these sites and similar chemically induced mutations by generalized transduction with phage 80 alpha have defined the order and relationship of these insertion sites and provided a detailed map of this region of the chromosome, including the orientation of the trp operon. The results of this study and a limited phenotypic characterization of the mutants have shown that the divergent pathway from aspartate to lysine, threonine, and methionine, several reactions in tyrosine biosynthesis, and the entire tryptophan operon are determined by this region of the chromosome. The linkage results obtained by transduction have been compared with similar data obtained previously by transformation; this comparison suggests the existence, between thy and lys, of a preferred headful cutting site for transducing phage DNA morphogenesis from the host chromosome.