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Title
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Iron, DtxR, and the regulation of diphtheria toxin expression.
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Authors
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X.Tao,
N.Schiering,
H.Y.Zeng,
D.Ringe,
J.R.Murphy.
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Ref.
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Mol Microbiol, 1994,
14,
191-197.
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PubMed id
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Abstract
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In recent years considerable advances have been made in the understanding of the
molecular basis of iron-mediated regulation of diphtheria toxin expression. The
tox gene has been shown to be regulated by the heavy metal ion-activated
regulatory element DtxR. In the presence of divalent heavy metal ions, DtxR
becomes activated and binds to a 9 bp interrupted palindromic sequence. The
consensus-binding site has been determined by both the sequence analysis of
DtxR-responsive operators cloned from genomic libraries of Corynebacterium
diphtheriae as well as by in vitro genetic methods using cyclic amplification of
selected targets (CASTing). It is now clear that DtxR functions as a global
iron-sensitive regulatory element in the control of gene expression in C.
diphtheriae. In addition, the metal ion-activation domain of DtxR is being
characterized by both mutational analysis and determination of the X-ray
structure at 3.0 A resolution.
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