title: Deletion of the Escherichia coli O14:K7 O antigen gene cluster.
abstract: Escherichia coli O14:K7 is a rough strain, lacking a typical O antigen, in which the enterobacterial common antigen is attached to the lipopolysaccharide core. The rough phenotype was previously mapped to the O antigen gene cluster; however, the nature of the nonfunctional locus was not defined. In this study, we have shown that the O antigen gene cluster of an O14:K7 type strain (Su4411/41) was most likely deleted via homologous recombination between the GDP-mannose pathway genes (manB and manC) of the colanic acid and O antigen gene clusters. A similar recombination event has previously been inferred for the deletion of E. coli Sonnei chromosomal O antigen genes. Therefore, recombination between the GDP-mannose pathway genes provides a convenient mechanism for the deletion of O antigen genes, which may occur if the typical O antigen becomes redundant.
authors.affiliation: School of Molecular and Microbial Sciences, University of Sydney, New South Wales, Australia.
authors.forename: Slade O
authors.initials: SO
authors.lastname: Jensen
authors.forename: Peter R
authors.initials: PR
authors.lastname: Reeves
mesh_terms: D004926:Escherichia coli / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D017353:Gene Deletion; D006155:Guanosine Diphosphate Mannose / Q000378:metabolism; D008358:Mannose / Q000096:biosynthesis*; D019081:O Antigens / Q000096:biosynthesis / Q000235:genetics*; D011134:Polysaccharides
chemical_list: D019081:O Antigens; D011134:Polysaccharides; D006155:Guanosine Diphosphate Mannose; C004275:colanic acid; D008358:Mannose