The Streptococcus mutans GlnR protein exhibits an increased affinity for the glnRA operon promoter when bound to GlnK

Castellen, Patrícia; Rego, Fabiane Gomes de Moraes; Portugal, Magda Eline Guerrart; Benelli, Elaine Machado

doi:10.1590/s0100-879x2011007500138

Cited by 12 publications

(16 citation statements)

References 33 publications

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“…These data suggest an inhibitory effect of GlnR on the transcription of the glnRA operon, indicating a negative autoregulation of its own transcription. Such a negative autoregulation has been shown for several bacteria like B. subtilis (Schreier et al ., ; Brown & Sonenshein, ), Bacillus cereus (Nakano & Kimura, ), L. lactis (Larsen et al ., ), S. pneumoniae (Kloosterman et al ., ), and S. mutans (Castellen et al ., ). However, in L. monocytogenes , the GlnR‐mediated repression is influenced not only by nitrogen source but also by temperature, weakest repression found at 24 °C/Gln.…”

Section: Resultsmentioning

confidence: 97%

Temperature- and nitrogen source-dependent regulation of GlnR target genes inListeria monocytogenes

Kaspar

Auer

Schardt

et al. 2014

FEMS Microbiol Lett

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The ubiquitous pathogen Listeria monocytogenes lives either saprophytically in the environment or within cells in a vertebrate host, thus adapting its lifestyle to its ecological niche. Growth experiments at 24 and 37 °C (environmental and host temperature) with ammonium or glutamine as nitrogen sources revealed that ammonium is the preferred nitrogen source of L. monocytogenes. Reduced growth on glutamine is more obvious at 24 °C. Global transcriptional microarray analyses showed that the most striking difference in temperature-dependent transcription was observed for central nitrogen metabolism genes, glnR (glutamine synthetase repressor GlnR), glnA (glutamine synthetase GlnA), amtB (ammonium transporter AmtB), glnK (PII regulatory protein GlnK), and gdh (glutamate dehydrogenase) when cells were grown on glutamine. When grown on ammonium, both at 24 and 37 °C, the transcriptional level of these genes resembles that of cells grown with glutamine at 37 °C. Electrophoretic mobility shift assay studies and qPCR analyses in the wild-type L. monocytogenes and the deletion mutant L. monocytogenes ∆glnR revealed that the transcriptional regulator GlnR is directly involved in temperature- and nitrogen source-dependent regulation of the respective genes. Glutamine, a metabolite known to influence GlnR activity, seems unlikely to be the (sole) intracellular signal mediating this temperature-and nitrogen source-dependent metabolic adaptation.

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Section: Resultsmentioning

confidence: 97%

Temperature- and nitrogen source-dependent regulation of GlnR target genes inListeria monocytogenes

Kaspar

Auer

Schardt

et al. 2014

FEMS Microbiol Lett

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“…However, at the same time, it is absent in many others, including all analyzed Lactobacillaceae. Moreover, GlnK was shown to interact with TnrA in B. subtilis [9,10] and GlnR in S. mutans [11]. …”

Section: Resultsmentioning

confidence: 99%

“…In fact, in L. lactis it was shown that expression of the amtB-glnK operon is controlled by GlnR but also by CodY [62]. In S. mutans it was shown by electrophoretic mobility shift assay that GlnR binds to the promoter region of both the glnRA and amtB-glnK operon [11]. The same study identified GlnK as an activator of GlnR DNA-binding.…”

Section: Resultsmentioning

confidence: 99%

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Comparative genome analysis of central nitrogen metabolism and its control by GlnR in the class Bacilli

et al. 2012

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BackgroundThe assimilation of nitrogen in bacteria is achieved through only a few metabolic conversions between alpha-ketoglutarate, glutamate and glutamine. The enzymes that catalyze these conversions are glutamine synthetase, glutaminase, glutamate dehydrogenase and glutamine alpha-ketoglutarate aminotransferase. In low-GC Gram-positive bacteria the transcriptional control over the levels of the related enzymes is mediated by four regulators: GlnR, TnrA, GltC and CodY. We have analyzed the genomes of all species belonging to the taxonomic families Bacillaceae, Listeriaceae, Staphylococcaceae, Lactobacillaceae, Leuconostocaceae and Streptococcaceae to determine the diversity in central nitrogen metabolism and reconstructed the regulation by GlnR.ResultsAlthough we observed a substantial difference in the extent of central nitrogen metabolism in the various species, the basic GlnR regulon was remarkably constant and appeared not affected by the presence or absence of the other three main regulators. We found a conserved regulatory association of GlnR with glutamine synthetase (glnRA operon), and the transport of ammonium (amtB-glnK) and glutamine/glutamate (i.e. via glnQHMP, glnPHQ, gltT, alsT). In addition less-conserved associations were found with, for instance, glutamate dehydrogenase in Streptococcaceae, purine catabolism and the reduction of nitrite in Bacillaceae, and aspartate/asparagine deamination in Lactobacillaceae.ConclusionsOur analyses imply GlnR-mediated regulation in constraining the import of ammonia/amino-containing compounds and the production of intracellular ammonia under conditions of high nitrogen availability. Such a role fits with the intrinsic need for tight control of ammonia levels to limit futile cycling.

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“…This complexity makes it difficult to infer a potential role for P II in the proposed PipX complexes. Notably, P II proteins acting in complexes with DNA-binding transcriptional regulators have been reported in other systems (45)(46)(47).…”

Section: Ntca-independent Expression Patterns and Functions Of Pipx Rmentioning

confidence: 99%

PipX, the coactivator of NtcA, is a global regulator in cyanobacteria

Espinosa¹,

Rodríguez

Salinas³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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To modulate the expression of genes involved in nitrogen assimilation, the cyanobacterial P II -interacting protein X (PipX) interacts with the global transcriptional regulator NtcA and the signal transduction protein P II , a protein found in all three domains of life as an integrator of signals of the nitrogen and carbon balance. PipX can form alternate complexes with NtcA and P II , and these interactions are stimulated and inhibited, respectively, by 2-oxoglutarate, providing a mechanistic link between P II signaling and NtcA-regulated gene expression. Here, we demonstrate that PipX is involved in a much wider interaction network. The effect of pipX alleles on transcript levels was studied by RNA sequencing of S. elongatus strains grown in the presence of either nitrate or ammonium, followed by multivariate analyses of relevant mutant/control comparisons. As a result of this process, 222 genes were classified into six coherent groups of differentially regulated genes, two of which, containing either NtcA-activated or NtcA-repressed genes, provided further insights into the function of NtcA-PipX complexes. The remaining four groups suggest the involvement of PipX in at least three NtcA-independent regulatory pathways. Our results pave the way to uncover new regulatory interactions and mechanisms in the control of gene expression in cyanobacteria.nitrogen regulation | transcription | translation | photosynthesis

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The Streptococcus mutans GlnR protein exhibits an increased affinity for the glnRA operon promoter when bound to GlnK

Cited by 12 publications

References 33 publications

Temperature- and nitrogen source-dependent regulation of GlnR target genes inListeria monocytogenes

Temperature- and nitrogen source-dependent regulation of GlnR target genes inListeria monocytogenes

Comparative genome analysis of central nitrogen metabolism and its control by GlnR in the class Bacilli

PipX, the coactivator of NtcA, is a global regulator in cyanobacteria

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