title: Identification of a gene involved in polysaccharide export as a transcription target of FruA, an essential factor for Myxococcus xanthus development.
abstract: Fruiting body development in Myxococcus xanthus is a multicellular event that is coordinated by exchanging intercellular signals. FruA is a transcription factor essential for fruiting body development and is thought to play a key role in the C-signal pathway. Here we present the first identification of a gene regulated by FruA. The gene was isolated from a genomic library via in vitro selection in a DNA binding assay by using the DNA-binding domain of FruA tagged with His(8) at the C-terminal end (FruA-DBD-H(8)). The gene, named fdgA (FruA-dependent gene A), encodes a protein homologous to the outer-membrane auxiliary family protein involved in the polysaccharide export system. FruA-DBD-H(8) bound the upstream promoter region of the fdgA gene from nucleotide -89 to nucleotide -64 with respect to the transcription initiation site, which was required for the induction of fdgA expression during development. fdgA mRNA induced during development was absent in a fruA deletion strain. The deletion of fdgA resulted in defective fruiting body formation and reduced sporulation efficiency (1% that of the parent strain). Moreover, FruA was required for the developmental expression of sasA, which is also involved in the biosynthesis of the lipopolysaccharide O-antigen and is required for fruiting body development. Furthermore, the expression of both fdgA and sasA was partially dependent on the C-signal. These findings expand our understanding of the signal transduction pathway mediated by FruA during development in M. xanthus.
authors.affiliation: Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ueki
authors.forename: Sumiko
authors.initials: S
authors.lastname: Inouye
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D001692:Biological Transport; D004247:DNA / Q000737:chemistry; D017353:Gene Deletion; D015723:Gene Library; D016678:Genome; D007763:Lac Operon; D008070:Lipopolysaccharides / Q000737:chemistry; D008969:Molecular Sequence Data; D009154:Mutation; D016941:Myxococcus xanthus / Q000378:metabolism*; D010641:Phenotype; D011134:Polysaccharides / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; C104848:FruA protein, Myxococcus xanthus; D008070:Lipopolysaccharides; D011134:Polysaccharides; D012333:RNA, Messenger; D014157:Transcription Factors; D004247:DNA