title: Location of F plasmid transfer operon genes traC and traW and identification of the traW product.
abstract: As part of an analysis of the conjugative transfer genes associated with the expression of F pili by plasmid F, we have investigated the physical location of the traC and traW genes. We found that plasmid clones carrying a 2.95-kilobase EcoRI-EcoRV F transfer operon fragment were able to complement transfer of F lac traC mutants and expressed an approximately 92,000-dalton product that comigrates with TraC. We also found that traW-complementing activity was expressed from plasmids carrying a 900-base-pair SmaI-HincII fragment. The traW product was identified as an approximately 23,000-dalton protein. The two different F DNA fragments that expressed traC and traW activities do not overlap. Our data indicate that the traC gene is located in a more-tra operon promoter-proximal position than suggested on earlier maps and that traW is distal to traC. These results resolve a long-standing question concerning the relationship of traW to traC. The clones we have constructed are expected to be useful in elucidating the role of proteins TraC and TraW in F-pilus assembly.
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics*; D005144:F Factor; D010861:Fimbriae, Bacterial / Q000502:physiology; D005796:Genes; D005798:Genes, Bacterial; D005822:Genetic Vectors; D009154:Mutation; D009876:Operon; D010957:Plasmids
chemical_list: D001426:Bacterial Proteins