Ania regulates reserve polymer accumulation and global protein expression in Rhizobium etli


Por: Encarnación S., Del Carmen Vargas M., Dunn M.F., Dávalos A., Mendoza G., Mora Y., Mora J.

Publicada: 1 ene 2002
Resumen:
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::OSmr/Spr mutant CAR1, which is unable to synthesize poly-ß-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 ß-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.

Filiaciones:
Encarnación S.:
 Programa de Ingenieria Metabolica, Ctr. Inves. sobre Fijacion Nitrogeno, Univ. Nacional Autonoma de Mexico, Apartado Postal 565-A, Cuernavaca, Morelos CP62210, Mexico

Del Carmen Vargas M.:
 Programa de Ingenieria Metabolica, Ctr. Inves. sobre Fijacion Nitrogeno, Univ. Nacional Autonoma de Mexico, Apartado Postal 565-A, Cuernavaca, Morelos CP62210, Mexico

Dunn M.F.:
 Programa de Ingenieria Metabolica, Ctr. Inves. sobre Fijacion Nitrogeno, Univ. Nacional Autonoma de Mexico, Apartado Postal 565-A, Cuernavaca, Morelos CP62210, Mexico

Dávalos A.:
 Programa de Ingenieria Metabolica, Ctr. Inves. sobre Fijacion Nitrogeno, Univ. Nacional Autonoma de Mexico, Apartado Postal 565-A, Cuernavaca, Morelos CP62210, Mexico

Mendoza G.:
 Programa de Ingenieria Metabolica, Ctr. Inves. sobre Fijacion Nitrogeno, Univ. Nacional Autonoma de Mexico, Apartado Postal 565-A, Cuernavaca, Morelos CP62210, Mexico

Mora Y.:
 Programa de Ingenieria Metabolica, Ctr. Inves. sobre Fijacion Nitrogeno, Univ. Nacional Autonoma de Mexico, Apartado Postal 565-A, Cuernavaca, Morelos CP62210, Mexico

Mora J.:
 Programa de Ingenieria Metabolica, Ctr. Inves. sobre Fijacion Nitrogeno, Univ. Nacional Autonoma de Mexico, Apartado Postal 565-A, Cuernavaca, Morelos CP62210, Mexico
ISSN: 00219193
Editorial
AMER SOC MICROBIOLOGY, 1752 N ST NW, WASHINGTON, DC 20036-2904 USA, Estados Unidos America
Tipo de documento: Article
Volumen: 184 Número: 8
Páginas: 2287-2295
WOS Id: 000174669100027
ID de PubMed: 11914361
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