Curation Information

Publication
Induction of the ferritin gene (ftnA) of Escherichia coli by Fe(2+)-Fur is mediated by reversal of H-NS silencing and is RyhB independent.;Nandal A, Huggins CC, Woodhall MR, McHugh J, Rodríguez-Quiñones F, Quail MA, Guest JR, Andrews SC;Molecular microbiology 2010 Feb; 75(3):637-57 [20015147]
TF
H-NS [P0ACF8, view regulon]
Reported TF sp.
Escherichia coli str. K-12 substr. MG1655
Reported site sp.
Escherichia coli str. K-12 substr. MG1655
Created by
Grace Chandler
Curation notes
-

Experimental Process

Western blot analysis showed FtnA levels are growth phase independent, but Fur and iron dependent, with expression levels lower in their presence. A ftna-lacZ translational fusion strand was used to further confirm the iron/fur dependence of FtnA expression. SdiA was shown to regulate ftnA, but is not responsible for its iron depletion induction. Western blot analysis showed that H-NS is required for fur-dependent regulation of FtnA. Fur dependent induction of ftnA expression requiring H-NS was confirmed by ftnA-lacZ expression comparison in wild type, hns, fur and hns fur strains. Gel retardation assays was used to show H-NS and Fur specifically interact with the ftnA promoter. In vitro transcription assays revealed Fur counteracts H-NS repression of FtnA transcription. DNAse I footprinting identified the location of the Fur binding sites and the H-NS binding sites in the ftnA binding region. A Fur H-NS combination footprinting reaction showed H-NS and Fur compete for the same region in the ftnA promoter.

Transcription Factor Binding Sites


ATATTTTAAT
GCTGATTAAAGAAATA
ATTCGTATTTTTAATAATTGAAGTTTATATTTTA
TTTGCAAATAATAAAATAACAAATTATAGTGA
AACAAATATAAC
ATATTTTAAT
GCTGATTAAAGAAATA
ATTCGTATTTTTAATAATTGAAGTTTATATTTTA
TTTGCAAATAATAAAATAACAAATTATAGTGA
AACAAATATAAC

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