New IS10 transposition vectors based on a gram-positive replication origin.

We describe below a set of plasmid-based vehicles which can be used for delivery of IS10-derived transposons into Gram- bacteria. These vehicles replicate via a Gram+ plasmid origin that is inactive in Escherichia coli; they are easily maintained in Bacillus subtilis. Transposons are introduced by electroporation or transformation with the plasmid, and as in previous delivery systems, transpositions are selected with the appropriate antibiotic. This system should be particularly useful in situations where the standard delivery vehicles, based on bacteriophage lambda, are inappropriate. The system described incorporates a number of useful features: a variety of antibiotic markers (Er, Cm, Km or Tc), a polylinker containing restriction sites for rare-cutting endonucleases to facilitate physical mapping of chromosomal insertions, a mutant transposase that confers a relaxation in insertion specificity and positioning of the transposase-encoding gene outside of the transposing segment to ensure the stability of insertions once isolated.