Curation Information

Publication: NrrA, a nitrogen-regulated response regulator protein, controls glycogen catabolism in the nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120.;Ehira S, Ohmori M;The Journal of biological chemistry 2011 Nov 4; 286(44):38109-14 [21926170]
TF: NrrA [K7WA79, view regulon]
Reported TF sp.: Anabaena sp. strain PCC7120
Reported site sp.: Nostoc sp. PCC 7120
Created by: Grace Chandler
Curation notes: -

Experimental Process

qRT-PCR demonstrated activation of glgP1 expression by NrrA. Activation of hetR by NrrA had been identified in previous studies. EMSA confirmed binding of NrrA to the glgP1 and hetR promoter regions. Multiple sequence alignment of glgP1 promoters from Anabaena spp. and Nostoc spp. identified a conserved NrrA binding motif. EMSA showed that deletion of this conserved sequence in the glgP promoter abolished NrrA binding.

Transcription Factor Binding Sites

Sites reported in the paper
Sites matched in the genome

AAAGTCA
AATGTCA

Gene Regulation

Regulated genes for each binding site are displayed below. Gene regulation diagrams show binding sites, positively-regulated genes, negatively-regulated genes, both positively and negatively regulated genes, genes with unspecified type of regulation. For each indvidual site, experimental techniques used to determine the site are also given.

Site sequence	Regulated genes	Gene diagram	Experimental techniques	TF function	TF type
AAAGTCA	all1272		Experimental technique details EMSA (ECO:0001807) EMSA - ECO:0001807 Electro-mobility shift-assays (or gel retardation assays) are a standard way of assessing TF-binding. A fragment of DNA of interest is amplified and labeled with a fluorophore. The fragment is left to incubate in a solution containing abundant TF and non-specific DNA (e.g. randomly cleaved DNA from salmon sperm, of all things) and then a gel is run with the incubated sample and a control (sample that has not been in contact with the TF). If the TF has bound the sample, the complex will migrate more slowly than unbound DNA through the gel, and this retarded band can be used as evidence of binding. The unspecific DNA ensures that the binding is specific to the fragment of interest and that any non-specific DNA-binding proteins left-over in the TF purification will bind there, instead of on the fragment of interest. EMSAs are typically carried out in a bunch of fragments, shown as multiple double (control+experiment) lanes in a wide picture. Certain additional controls are run in at least one of the fragments to ascertain specificity. In the most basic of these, specific competitor (the fragment of interest or a known positive control, unlabelled) is added to the reaction. This should sequester the TF and hence make the retardation band disappear, proving that the binding is indeed specific - Experimental technique details Multiple sequence alignment (MSA) (ECO:0005556) Multiple sequence alignment (MSA) - ECO:0005556 MSA can be used to align promoter regions and highlight regions of conservation that may be indicative of transcription factor binding sites. - Experimental technique details qRT-PCR [RNA] (ECO:0001808) qRT-PCR [RNA] - ECO:0001808 Quantitative Reverse-Transcription PCR is a modification of PCR in which RNA is first reverse transcribed into cDNA and this is amplified measuring the product (qPCR) in real time. It therefore allows one to analyze transcription by directly measuring the product (RNA) of a gene's transcription. If the gene is transcribed more, the starting product for PCR is larger and the corresponding volume of amplification is also larger. - Experimental technique details Visual sequence inspection (nan) Visual sequence inspection - nan Visual inspection of promoter region to identify putative binding sites based on previous knowledge -	activator	not specified
AATGTCA	hetR		Experimental technique details EMSA (ECO:0001807) EMSA - ECO:0001807 Electro-mobility shift-assays (or gel retardation assays) are a standard way of assessing TF-binding. A fragment of DNA of interest is amplified and labeled with a fluorophore. The fragment is left to incubate in a solution containing abundant TF and non-specific DNA (e.g. randomly cleaved DNA from salmon sperm, of all things) and then a gel is run with the incubated sample and a control (sample that has not been in contact with the TF). If the TF has bound the sample, the complex will migrate more slowly than unbound DNA through the gel, and this retarded band can be used as evidence of binding. The unspecific DNA ensures that the binding is specific to the fragment of interest and that any non-specific DNA-binding proteins left-over in the TF purification will bind there, instead of on the fragment of interest. EMSAs are typically carried out in a bunch of fragments, shown as multiple double (control+experiment) lanes in a wide picture. Certain additional controls are run in at least one of the fragments to ascertain specificity. In the most basic of these, specific competitor (the fragment of interest or a known positive control, unlabelled) is added to the reaction. This should sequester the TF and hence make the retardation band disappear, proving that the binding is indeed specific - Experimental technique details Visual sequence inspection (nan) Visual sequence inspection - nan Visual inspection of promoter region to identify putative binding sites based on previous knowledge -	activator	not specified