NUCLEOTIDE-SEQUENCE AND PROPERTIES OF THE TRANSPOSON-LIKE STRUCTURE FROM THE CHROMOSOME OF BORDETELLA-PERTUSSIS

The 2.3 kb BamHI-EcoRI subclone has been isolated and sequenced from t he 15 kb BamHI chromosomal fragment of Bordetella pertussis comprising also the vir gene. The sequence contained one copy of a transposon-li ke structure, very similar to the RSs of B. pertussis recently charact erized, the unique sequence of B. pertussis chromosomal DNA and an inv erted sequence complementary to 402 bp of 3' end of the B. pertussis R S element. The fragment of plasmid pUC4K containing the gene for kanam ycin resistance (Km) was integrated in the XhoI site of the unique por tion of the transposon-like structure of plasmid DNA (Ap(r), Km(r)). T he clones in amount of 2% tested had the Ap-S phenotype. The recombina nt plasmid from the Ap(s) phenotype clones lost one of the repeats and a portion of the gene bla as a result of deletion. The conclusion is drawn that RSs of B. pertussis stimulate the formation of deletions.