title: AniA regulates reserve polymer accumulation and global protein expression in Rhizobium etli.
abstract: Previously, it was reported that the oxidative capacity and ability to grow on carbon sources such as pyruvate and glucose were severely diminished in the Rhizobium etli phaC::OmegaSm(r)/Sp(r) mutant CAR1, which is unable to synthesize poly-beta-hydroxybutyric acid (PHB) (M. A. Cevallos, S. Encarnación, A. Leija, Y. Mora, and J. Mora, J. Bacteriol. 178:1646-1654, 1996). By random Tn5 mutagenesis of the phaC strain, we isolated the mutants VEM57 and VEM58, both of which contained single Tn5 insertions and had recovered the ability to grow on pyruvate or glucose. Nucleotide sequencing of the region surrounding the Tn5 insertions showed that they had interrupted an open reading frame designated aniA based on its high deduced amino acid sequence identity to the aniA gene product of Sinorhizobium meliloti. R. etli aniA was located adjacent to and divergently transcribed from genes encoding the PHB biosynthetic enzymes beta-ketothiolase (PhaA) and acetoacetyl coenzyme A reductase (PhaB). An aniA::Tn5 mutant (VEM5854) was constructed and found to synthesize only 40% of the wild type level of PHB. Both VEM58 and VEM5854 produced significantly more extracellular polysaccharide than the wild type. Organic acid excretion and levels of intracellular reduced nucleotides were lowered to wild-type levels in VEM58 and VEM5854, in contrast to those of strain CAR1, which were significantly elevated. Proteome analysis of VEM58 showed a drastic alteration of protein expression, including the absence of a protein identified as PhaB. We propose that the aniA gene product plays an important role in directing carbon flow in R. etli.
authors.affiliation: Programa de Ingeniería Metabólica, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos CP62210, Mexico. encarnac@cifn.unam.mx
authors.forename: Sergio
authors.initials: S
authors.lastname: Encarnación
authors.forename: María
authors.initials: M
authors.lastname: del Carmen Vargas
authors.forename: Michael F
authors.initials: MF
authors.lastname: Dunn
authors.forename: Araceli
authors.initials: A
authors.lastname: Dávalos
authors.forename: Guillermo
authors.initials: G
authors.lastname: Mendoza
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Mora
authors.forename: Jaime
authors.initials: J
authors.lastname: Mora
mesh_terms: D000217:Acyltransferases / Q000502:physiology; D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000737:chemistry / Q000502:physiology*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000502:physiology*; D001426:Bacterial Proteins / Q000096:biosynthesis*; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D005816:Genetic Complementation Test; D006003:Glycogen / Q000378:metabolism; D006885:Hydroxybutyrates / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D011091:Polyesters / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D020543:Proteome; D019289:Pyruvic Acid / Q000378:metabolism; D012231:Rhizobium / Q000235:genetics / Q000378:metabolism*; D013559:Symbiosis; D000094122:Polyhydroxybutyrates
chemical_list: D000217:Acyltransferases; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D006003:Glycogen; D006885:Hydroxybutyrates; D011091:Polyesters; D011135:Polysaccharides, Bacterial; D020543:Proteome; D019289:Pyruvic Acid; C077531:aniA protein, Neisseria gonorrhoeae; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates; C060970:poly-beta-hydroxybutyrate polymerase