TRANSPOSON TN917PF1 MUTAGENESIS IN BACILLUS-LICHENIFORMIS

The plasmid pTnPF1 containing the transposon Tn917PF1 was introduced into the protoplasts of two Bacillus licheniformis strains in the presence of polyethylene glycol. Transpositions were produced at high temperature which inhibited plasmid replication and kanamycin was used for selection. Transposon Tn917PF1 was inserted randomly into the bacterial chromosome, producing different auxotrophic, prophage BLF and bacitracin-non-producing mutants. The auxotrophic mutant phenotypes were characterized by the Holliday-test and some mutations by hybridization with a transposon DNA probe. Insertions for the entire chromosome or for the prophage genophore were found at random, but preferred target sites were detected within limited regions, like the bacitracin synthetase or sulphate reductase genes. The partial physical map of the chromosomal region of bacitracin synthetase was constructed based on the hybridization patterns of insertion mutants.