FIG. 3.
Excision system II. (A) A region of the TP901-1 genome is shown at the top, with relevant restriction sites indicated (EV, EcoRV; N, NsiI; H, HindIII; X, XhoI; EI, EcoRI). The numbering of the base pairs shown at the top corresponds to the numbering described in footnote a of Table 1. DNA is shown as a thin line; open reading frames are shown as black arrows. The TP901-1 integrase is encoded by orf1. The attP site is depicted as a black box. The region of the TP901-1 genome inserted in excision vector pAB174a is indicated. pAB174a is integrated into attB in JM342 to obtain strain AB174a. (B) Regions of the TP901-1 genome present in the protein donor plasmids and frequencies of FUr cells obtained when these plasmids are introduced in AB174a.