A role for the signal transduction protein PII in the control of nitrate/nitrite uptake in a cyanobacterium

FEBS Letters

Tandeau de Marsac, Nicole²  Flores, Enrique¹  Herrero, Antonia¹  Lee, Hyun-Mi²  Houmard, Jean² 

[1] Instituto de Bioquı́mica Vegetal y Fotosı́ntesis, Centro de Investigaciones Cientı́ficas Isla de la Cartuja, Avda. Américo Vespucio s/n, E-41092 Sevilla, Spain;Département de Biochimie et Génétique Moléculaire, Unité de Physiologie Microbienne, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France

关键词: Nitrogen metabolism;    Ammonium inhibition;    Regulation;    glnB gene product;    Synechococcus sp. strain PCC 7942;   

DOI  :  10.1016/S0014-5793(98)00451-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In the cyanobacterium Synechococcus sp. strain PCC 7942, ammonium exerts a rapid and reversible inhibition of the nitrate and nitrite uptake, and the P_II protein (GlnB) is differentially phosphorylated depending on the intracellular N/C balance. RNA/DNA hybridizations, as well as nitrate and nitrite uptake experiments, were carried out with the wild-type strain and a P_II-null mutant. The transcriptional control by ammonium of the expression of the nir-nrtABCD-narB operon remained operative in the mutant but, in contrast to the wild-type strain, the mutant took up nitrate and nitrite even in the presence of ammonium. Moreover, the wild-type phenotype was restored by insertion of a copy of the wild-type glnB gene in the genome of the P_II-null mutant. These results indicate that the unphosphorylated form of P_II is involved in the short-term inhibition by ammonium of the nitrate and nitrite uptake in Synechococcus sp. strain PCC 7942.

【 授权许可】

Unknown