Curation Information

The AbrB2 autorepressor, expressed from an atypical promoter, represses the hydrogenase operon to regulate hydrogen production in Synechocystis strain PCC6803.;Dutheil J, Saenkham P, Sakr S, Leplat C, Ortega-Ramos M, Bottin H, Cournac L, Cassier-Chauvat C, Chauvat F;Journal of bacteriology 2012 Oct; 194(19):5423-33 [22865847]
Sll0822 [Q55432, view regulon]
Reported TF sp.
Synechocystis sp. PCC 6803
Reported site sp.
Synechocystis sp. PCC 6803
Created by
Dinara Sagitova
Curation notes

Experimental Process

EMSA with promoter fragments of different length identified the AbrB2 binding region. abrB2-cat reporter assays demonstrated that AbrB2 is an autorepressor. 5'RACE analysis was used to map the transcription start site of abrB2. RT-PCR showed that hoxEFUYH operon was at least 2.5-fold more abundant in the abrB2-deleted mutant than in the WT strain. EMSA with a series of 5' deletions of the hox operon promoter identified the AbrB2 binding region. A possible consensus sequence (TT(N5)AAC) was determined by searching for a motif that occurs in the abrB2 and the hox promoter subfragments. Site-directed mutagenesis verified that the promoter activity increased when TT -> GG substitutions were made.

Transcription Factor Binding Sites


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
... ... MYO_125970 MYO_125980
Experimental technique details CAT reporter gene assays (ECO:0005617) - Experimental technique details EMSA (ECO:0001807) - Experimental technique details Motif-discovery (ECO:0005558) - Experimental technique details Site directed mutagenesis (ECO:0005667) - repressor not specified