IDENTIFICATION AND NUCLEOTIDE-SEQUENCE ANALYSIS OF A TRANSFER-RELATEDREGION IN THE STREPTOCOCCAL CONJUGATIVE TRANSPOSON TN5252

To obtain a functional map of Tn5252, a 47.5-kb streptococcal conjugat ive transposon, a series of defined deletion and insertion mutations w ere introduced within the transposon. Interruptions at several regions were found to affect the conjugal transposition functions of the elem ent in filter-mating experiments. The nucleotide sequence of the left terminus of Tn5252 showed two open reading frames, ORF1 and ORF2, adjo ining the att site. The organization of this region and the structure of the predicted integrase encoded by ORF1 were found to be similar to those of other site-specific recombination systems.