Figure 4
Sketch drawing of the replicative transposition of Tn ces :: km into recipient chromosome and the strategy of hybridization. The transposase-mediated fusion of pTnkm and the target molecules generate a third copy of ISces. There are two theoretically possible results of transposition, depending on which ISces is duplicated. Three probes 1, 2, and 3, indicated by dotted lines, represent an internal fragment of bla in cloning vector pUC18, ISces, and Km, respectively, were used for the survey of the transposition. The Nde I sites in kmRsmR transconjugants were indicated. No matter which ISces was duplicated, hybridization with probe 1 and 3, a 3.5 kb band and a 1.6 kb band is expected, respectively; with probe 2, besides the 1 kb and 3.5 kb expected bands, extra bands with variable sizes in each independent transconjugant are probably detected due to multi-transpositions. Although there is also a (remote) possibility for the duplication of the whole Tnces::km element, the result will be similar except that more bands with probe 2 are expected.