Transcriptional effects of the signal transduction protein PII (glnB gene product) on NtcA‐dependent genes in Synechococcus sp. PCC 7942

FEBS Letters

Flores, Enrique¹  Herrero, Antonia¹  Paz-Yepes, Javier¹ 

[1] Instituto de Bioquı́mica Vegetal y Fotosı́ntesis, CSIC-Universidad de Sevilla, Avda. Américo Vespucio s/n, 41092 Sevilla, Spain

关键词: Cyanobacteria;    GlnB;    Nitrogen assimilation genes;    Nitrogen control;   

DOI  :  10.1016/S0014-5793(03)00384-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

P_II proteins signal the cellular nitrogen status in numerous bacteria, and in cyanobacteria P_II is subjected to serine phosphorylation when the cells experience a high C to N balance. In the unicellular cyanobacterium Synechococcus sp. PCC 7942, the P_II protein (glnB gene product) is known to mediate the ammonium-dependent inhibition of nitrate and nitrite uptake. The analysis of gene expression through RNA/DNA hybridization indicated that a P_II-null mutant was also impaired in the induction of NtcA-dependent, nitrogen assimilation genes amt1 (ammonium permease), glnA (glutamine synthetase) and nir (nitrite reductase), as well as of the N-control gene ntcA, mainly under nitrogen deprivation. This gene expression phenotype of the glnB mutant could be complemented by wild-type P_II protein or by modified P_II proteins that cannot be phosphorylated and mimic either the phosphorylated (GlnB^S49D and GlnB^S49E) or unphosphorylated (GlnB^S49A) form of P_II. However, strains carrying the GlnB^S49D and GlnB^S49E mutant proteins exhibited higher levels of expression of nitrogen-regulated genes than the strains carrying the wild-type P_II or the GlnB^S49A protein.

【 授权许可】

Unknown