title: Involvement of the invertible G segment in bacteriophage mu tail fiber biosynthesis.
abstract: The orientation [G(+) or G(-)] of the invertible G segment of bacteriophage Mu DNA determines the host range specificity of the phage particles. In this study the hypothesis that the G segment genes are involved in synthesis of Mu tail fibers has been tested. Serum blocking power (SBP) assays demonstrated that among Mu late gene mutants only those defective in genes S or U encoded by the G segment were defective in G(+) SBP and that they lacked the same antigens. Electron microscopy of lysates produced by inversion-defective gin mutants (isolated by their inability to complement a hin inversion-defective mutant of the Salmonella phase variation segment) showed that G(+) phages with amber mutations in S or U made tail-fiberless particles with contracted tail sheaths. Inversion of G to the G(-) orientation or suppression of the amber mutations restored the normal phage particle morphology. These experiments demonstrate that genes S and U are required for Mu G(+) tail fiber biosynthesis and/or attachment.
mesh_terms: D000956:Antigens, Viral; D010583:Bacteriophage mu / Q000235:genetics* / Q000254:growth & development / Q000276:immunology / Q000378:metabolism; D007446:Chromosome Inversion; D004279:DNA, Viral / Q000235:genetics*; D005814:Genes, Viral; D007106:Immune Sera; D008242:Lysogeny; D008854:Microscopy, Electron; D009154:Mutation; D009500:Neutralization Tests; D014764:Viral Proteins / Q000096:biosynthesis / Q000235:genetics*; D017376:Viral Tail Proteins
chemical_list: D000956:Antigens, Viral; D004279:DNA, Viral; D007106:Immune Sera; D014764:Viral Proteins; D017376:Viral Tail Proteins