Nucleotide Sequence Analysis of Integrative Conjugative Element Tn5253of Streptococcus pneumoniae

Abstract

ABSTRACTConjugative transposon Tn5253, an integrative conjugative element (ICE) ofStreptococcus pneumoniaecarrying thecatandtet(M) genes, was shown to be 64,528 bp in size and to contain 79 open reading frames, of which only 38 could be annotated. Two distinct genetic elements were found integrated into Tn5253: Tn5251(18,033 bp), of the Tn916-Tn1545family of ICEs, and Ωcat(pC194) (7,627 bp), which could not conjugate but was capable of intracellular mobility by excision, circularization, and integration by homologous recombination. The highest conjugation frequency of Tn5253was observed whenStreptococcus pyogeneswas the donor (6.7 × 10−3transconjugants/donor).