Characterization of P1argF derivatives from Escherichia coli K12 transduction

Abstract

Specialized transducing derivatives of the temperate bacteriophage P1 (P1std) are selected by transduction into recipients with deletions in the corresponding genes (Stodolsky 1973). When Escherichia coli K12 strains are used as donors in such transduction experiments, P1argF derivatives can be selected. The argF gene is unique to these strains (Glansdorff et al. 1967). Under these experimental conditions P1argF are formed with frequencies 10,000 times greater than other P1std. The majority of the P1argF derivatives that have been analyzed are indistinguishable by cleavage analyses. One such derivative, P1argF5 has been characterized in detail. Heteroduplex analysis against P1, P7, and P1CmO identified an 11 kb insertion of DNA precisely at the naturally occurring IS1 locus of P1. Cleavage analysis with EcoRI, BamHI and PstI confirmed this finding. To further define the argF insertion, a P1Cm13argF derivative was constructed having the IS1 sequences of Cm13 and argF in opposite orientation. Intrastrand annealing of P1Cm13argF5 DNA established that the argF segment is flanked by directly repeated IS1 sequences. The IS1-argF-IS1 segment is designated Tn2901. The assignment of the map position of the argF gene within the 11 kb insert of P1argF5 is discussed. The evolutionary significance of this finding and a model for P1argF formation is also presented.

Protein differentiation: a comparison of aspartate transcarbamoylase and ornithine transcarbamoylase from Escherichia coli K-12.

“…Such homology, when evaluated relative to the previously observed similarities, strongly suggests a common ancestry for these enzymes and is consistent with the possible involvement of tandem duplication(s) in the early evolution of the pyrB-encoded ATCase and the argIencoded OTCase-1 (12). The evolution of argF-encoded OTCase-2, on the other hand, has been proposed to have occurred either by genome duplication (13) or by transpositional events (14) that might have been intergeneric. From the observation that ATCase and OTCase are both involved in essential metabolic processes, it can be inferred that any duplicational event involving pyrB and argI must have occurred at a very early stage in biogenesis.…”

Analysis of Genome Plasticity in Pathogenic and Commensal Escherichia coli Isolates by Use of DNA Arrays

“…Therefore, these regions can be regarded as chromosomal variation hot spots and seem to be E. coli K-12 specific. It has been speculated that the 40-kb chromosomal segment downstream of the tRNA-encoding gene thrW (b0245 to b0286) has been acquired by horizontal gene transfer (55,57). The fact that the prophages which have been identified in E. coli strain MG1655 (36) are considered to have been recently acquired by E. coli laboratory strains, as they are missing in some natural E. coli isolates, has been mentioned before (43).…”

S-Fimbria-Encoding Determinant sfa I Is Located on Pathogenicity Island III 536 of Uropathogenic Escherichia coli Strain 536

“…The central part of this region contains the argF gene, flanked by IS1 elements. This structure, only present in E. coli K-12 strains, together with the high argF GC content (59%), argues for its acquisition by horizontal gene transfer (60,62). Interestingly, a 53-kb deletion compared to E. coli MG1655 has been identified in uropathogenic E. coli strain J96 in the vicinity of the foc determinant (51).…”