FIG. 1.

Plasmids for analyzing TP901-1 integrase-mediated recombination. (A) pBB-B304-P333 carries attB and attP recognition sites for the integrase in a direct orientation, flanking the lacZ gene, such that intramolecular integration mediated by the enzyme brings about excision of lacZ, which is detectable on X-Gal indicator plates as a change from blue colonies to white colonies. att sites of different sizes were cloned into pBB-B304-P333 in place of the full-length att sites to determine the minimal lengths of the recognition sites. (B) pTPInt expresses the TP901-1 integrase in E. coli by using the lac promoter. (C) pCMV-TPInt expresses the integrase in mammalian cells from the cytomegalovirus immediate early promoter. Amp^R, ampicillin resistance; Chlor^R, chloramphenicol resistance; Kan^R, kanamycin resistance; SV40 polyA, poly(A) addition site from simian virus 40.