Conduction of pEC22, a plasmid coding for MR.EcoT22I, mediated by a resident Tn3-like transposon, Tn5396

Abstract

pEC22 is a small plasmid that encodes the restriction-modification system MR.EcoT22I. Restriction and functional analysis of the plasmid identified the positions of genes encoding that system. The plasmid is able to be conducted by conjugal plasmids, a process mediated by a transposon contained within pEC22. This cryptic transposon, called Tn5396, was isolated from pEC22 and partially sequenced. The sequence of Tn5396 is for the most part typical of transposons of the Tn3 family and is most similar to that of Tn1000. The transposon differs from closely related transposons in that it lacks well-conserved sequences in the inverted-repeat region and has an unusually long terminal inverted repeat. Consideration of regions of internal sequence similarity in this and other transposons in the Tn3 family supports a theory of the mechanism by which the ends of Tn3-like transposons may maintain substantial identity between their inverted repeats over the course of evolutionary time.

An ABC‐type, high‐affinity urea permease identified in cyanobacteria

“…to generate strains bearing mutations in the ure and/or urt genomic regions. For the generation of strains CSAV1, CSAV2, CSAV3, CSAV4 and CSAV5, E. coli HB101 containing plasmid pCSAV12, pCSAV16, pCSAV12, pCSAV122 or pCSAV96, respectively, and helper plasmids pRL528 (Elhai and Wolk, 1988) and pRL591‐W45 (Elhai et al , 1994) was mixed with E. coli ED8654 carrying the conjugative plasmid pRL443 and thereafter with Anabaena sp. Exconjugants were isolated (Elhai and Wolk, 1988), and double recombinants were identified as clones resistant to the antibiotic for which resistance was encoded in the inserted gene cassette, resistant to sucrose and sensitive to the antibiotic for which the resistant determinant was present in the vector portion of the transferred plasmid and were confirmed by Southern or PCR analysis.…”

Nitrogen-regulated Genes for the Metabolism of Cyanophycin, a Bacterial Nitrogen Reserve Polymer

“…to generate strains bearing mutations in the cph1 or/and cph2 genomic regions. For generation of strains CSS7, CSS13, CSS21, and CSS25, E. coli strain HB101 containing plasmid pCSS35, pCSS39, pCSS52, or pCSS55 and helper plasmids pRL528 (26) and pRL591-W45 (27) or pRL623 (28) was mixed with E. coli ED8654 carrying the conjugative plasmid pRL443 and thereafter with Anabaena sp. For the generation of double mutants, plasmids pCSS39 and pCSS55 were transferred to strain CSS7 to generate strains CSS35 and CSS27, respectively, plasmid pCSS52 was transferred to strain CSS13 to generate strain CSS23, and plasmid pCSS55 was transferred to strain CSS21 to generate strain CSS36.…”

Four different integrative recombination events involved in the mobilization of the gonococcal 5.2kb beta-lactamase plasmid pSJ5.2 in Escherichia coli

“…It is known that the Insertion Sequence 1 play an active role in the formation of plasmid cointegrates and resolution by a replicative site-specific recombination mechanism (Crisona et al ., 1980; Masepohl and Puehler, 1983; Elhai et al ., 1994; Mahillon and Chandler, 1998; Martinez and De la Cruz, 1998; Shiga et al ., 2001; Grindley, N., 2002). The presence of two IS 1 copies within the 2.4 kb BamH1-BamH1 fragment in the pSJ5.2 insertion derivatives isolated from the E. coli transconjugants is compatible with the presence of at least one copy of IS 1 in both the 41 kb tet(M) conjugative and pSJ5.2 plasmids.…”