New derivatives of transposon tn5 suitable for mobilization of replicons, generation of operon fusions and induction of genes in Gram-negative bacteria

Three types of new variants of the broad-host-range transposen tn5 are described. (i) Tn5-mob derivatives with the new selective resistance (R) markers Gm R, Sp R and TcR facilitate the efficient mobilization of replicons within a wide range of Gram-negative bacteria, (ii) Promoter probe transposons carry the promoterless reporter genes lacZ, npt II, or luc, and NmR GmR or TcR as selective markers. These transposons can be used to generate transcriptional fusions upon insertion, thus facilitating accurate determinations of gene expression, (iii) Tn5-P-out derivatives carry the npt- or tac -promoter reading out from the transposen, and TcR, NmR or GmR genes. These variants allow the constitutive expression of downstream genes. The new Tn5 variants are available on mobilizable Escherichia coli vectors suitable as suicidal carriers for transposen mutagenesis of non-E. coli recipients and some on a phage λ mutant to be used for transposen mutagenesis in E. coli.