RppA, a transducer homologue, and MmrA, a multidrug transporter homologue, are involved in the biogenesis and/or assembly of polysaccharide in Myxococcus xanthus.
Myxococcus xanthus cells move by gliding, and form multicellular fruiting bodies under conditions of starvation. The authors cloned a gene, designated rppA (for receptor for polysaccharide production), which encodes a methyl-accepting protein homologous to the chemotaxis transducers in eubacteria. The rppA gene was co-transcribed with mmrA, a gene homologous to various multidrug transporter genes. The rppA or mmrA single mutants showed almost identical phenotypes to the wild-type strain; however, the rppA-mmrA double mutant exhibited reduced colony expansion, cell-cell agglutination and cellular reversal frequency. The double-mutant cells also showed less binding to Congo red, which mainly binds to fibril polysaccharide, than wild-type cells. Analysis of total polysaccharide in stationary-phase cells demonstrated that in the double mutant, polysaccharide levels were decreased by about 30 % as compared with the wild-type strain. These results indicated that RppA and MmrA play a role in the biogenesis and/or assembly of polysaccharide, and the phenotypes of the double mutant may be due to the reduction in fibril polysaccharide.
Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-Cho, Kagawa 761-0795, Japan.
Yoshio
Y
Kimura
Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-Cho, Kagawa 761-0795, Japan.
Saori
S
Ishida
Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-Cho, Kagawa 761-0795, Japan.
Hideki
H
Matoba
Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-Cho, Kagawa 761-0795, Japan.
Naoki
N
Okahisa
D018435:ATP Binding Cassette Transporter, Subfamily B / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D019450:Genes, MDR; D008969:Molecular Sequence Data; D009154:Mutation; D016941:Myxococcus xanthus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D010641:Phenotype; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid
D018435:ATP Binding Cassette Transporter, Subfamily B; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011135:Polysaccharides, Bacterial; C412036:RppA protein, Synechocystis