Iron, DtxR, and the regulation of diphtheria toxin expression
Article first published online: 27 OCT 2006
Volume 14, Issue 2, pages 191–197, October 1994
How to Cite
Tao, X., Schiering, N., Zeng, H.-y., Ringe, D. and Murphy, J. R. (1994), Iron, DtxR, and the regulation of diphtheria toxin expression. Molecular Microbiology, 14: 191–197. doi: 10.1111/j.1365-2958.1994.tb01280.x
- Issue published online: 27 OCT 2006
- Article first published online: 27 OCT 2006
- Received 11 May, 1994; revised 30 June, 1994; accepted 4 July, 1994.
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 (CAST-ing). 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 Å resolution.