title: sigma54, a vital protein for Myxococcus xanthus.
abstract: The rpoN gene encoding the transcription factor sigma54 in Myxococcus xanthus has been cloned using a heterologous rpoN probe. The sequence of the cross-hybridizing DNA confirmed the existence of an ORF 1518 bp long that encodes a well conserved member of the sigma54 family of sigma factors. Low- as well as high-stringency hybridizations detected only a single rpoN gene in the M. xanthus chromosome. In other bacteria, sigma54 is an alternative sigma, and null mutants are viable. However, all attempts to construct a strain containing a null mutation in the M. xanthus rpoN have been unsuccessful. Partial diploids of rpoN+/rpoN null are viable. Recombination experiments with such partial diploids showed the impossibility of constructing, either by segregation or by transduction, a viable null haploid under any of a wide range of growth conditions. The product of the rpoN gene, sigma54, therefore appears to be essential for growth in M. xanthus.
authors.affiliation: Department of Biochemistry, Stanford University School of Medicine, CA 94305-5307, USA.
authors.forename: I M
authors.initials: IM
authors.lastname: Keseler
authors.forename: D
authors.initials: D
authors.lastname: Kaiser
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D001665:Binding Sites; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000502:physiology*; D018628:Gene Dosage; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D016941:Myxococcus xanthus / Q000235:genetics / Q000254:growth & development*; D016366:Open Reading Frames / Q000235:genetics; D051877:RNA Polymerase Sigma 54; D015183:Restriction Mapping; D012270:Ribosomes / Q000378:metabolism; D017421:Sequence Analysis; D017384:Sequence Deletion / Q000235:genetics; D012808:Sigma Factor / Q000235:genetics / Q000502:physiology*; D014161:Transduction, Genetic / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D012808:Sigma Factor; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54