Pischl D L, Farrand S K
J Bacteriol. 1984 Jul;159(1):1-8. doi: 10.1128/jb.159.1.1-8.1984.
We have further characterized the transposon Tn5-facilitated chromosomal gene transfer system developed for Agrobacterium tumefaciens 15955. Using a strain whose chromosome contained Tn5, we compared the chromosome-mobilizing ability of plasmid pDP37 (containing Tn5) with that of its parent plasmid R68.45. For R68.45, we observed nonpolar transmission from multiple origins. For pDP37 we found polarized transmission from a single origin near ilv. When we examined the transmission gradients of a number of pDP37-containing donor strains each differing at the site of the chromosomal insertion we found just two classes. One set of donors transmitted markers with a gradient of Ilv+ greater than Rifr greater than His+ greater than Met+, whereas the second set transferred His+ greater than Rifr greater than Ilv+ greater than Met+. Using representatives from each transmission class of donor strains, we conducted matings to measure the degree of linkage between pairs of adjacent donor markers. From this information we developed a map of the A. tumefaciens 15955 chromosome. Attempts to isolate R-prime plasmids or Hfr-like donors were unsuccessful.
我们进一步对为根癌土壤杆菌15955开发的转座子Tn5促进的染色体基因转移系统进行了特性分析。使用一种染色体含有Tn5的菌株，我们比较了质粒pDP37（含有Tn5）及其亲本质粒R68.45动员染色体的能力。对于R68.45，我们观察到从多个起点的非极性传递。对于pDP37，我们发现从ilv附近的单个起点的极性传递。当我们检查许多在染色体插入位点不同的含pDP37供体菌株的传递梯度时，我们只发现了两类。一组供体传递标记的梯度为Ilv +大于Rifr大于His +大于Met +，而第二组传递His +大于Rifr大于Ilv +大于Met +。使用来自每个供体菌株传递类别的代表，我们进行了杂交以测量相邻供体标记对之间的连锁程度。根据这些信息，我们绘制了根癌土壤杆菌15955染色体的图谱。分离R-prime质粒或Hfr样供体的尝试均未成功。
