Integration-proficient Pseudomonas aeruginosa vectors for isolation of single-copy chromosomal lacZ and lux gene fusions

Transcriptional analyses of many genes of unknown function identified in whole genome sequencing projects or genes whose products are difficult to assay are facilitated by gene fusion technologies. Although many plasmid-based systems are available for constructing such gene fusions, they suffer from inherent problems that have been discussed before. To facilitate gene integration at a defined neutral site, various phage systems have been designed to integrate exogenous gene sequences at chromosomal phage attachment sites. In E. coli, lambda -based systems have been developed for single-copy chromosomal integration of gene fusions and other gene cassettes. We recently developed an integration-proficient phi CTX-based system for Pseudomonas aeruginosa, modeled after an approach that was previously described for mycobacterial integration vectors.