Tn1 transposition in the course of natural transformation enables horizontal antibiotic resistance spread in Acinetobacter baylyi

Transposons are genetic elements that change their intracellular genomic position by transposition and spread horizontally between bacteria when located on plasmids. It was recently discovered from fully heterologous DNA also occurs in the course of natural transformation. Here, we characterize molecular details constraints this process using replicative transposon Tn 1 naturally competent bacterium Acinetobacter baylyi . We find chromosomal insertion at low but detectable frequencies preferably around A. terminus replication. show is facilitated transient expression transposase resolvase encoded donor DNA. RecA protein essential for formation a circular, double-stranded cytoplasmic intermediate incoming DNA, RecO beneficial not process. Absence recipient RecBCD nuclease stabilizes intermediate. Based these results, suggest mechanistic model during