Transcriptional control of the iron-responsive fxbA gene by the mycobacterial regulator IdeR. Academic Article uri icon

Overview

abstract

  • Exochelin is the primary extracellular siderophore of Mycobacterium smegmatis, and the iron-regulated fxbA gene encodes a putative formyltransferase, an essential enzyme in the exochelin biosynthetic pathway (E. H. Fiss, Y. Yu, and W. R. Jacobs, Jr., Mol. Microbiol. 14:557-569, 1994). We investigated the regulation of fxbA by the mycobacterial IdeR, a homolog of the Corynebacterium diphtheriae iron regulator DtxR (M. P. Schmitt, M. Predich, L. Doukhan, I. Smith, and R. K. Holmes, Infect. Immun. 63:4284-4289, 1995). Gel mobility shift experiments showed that IdeR binds to the fxbA regulatory region in the presence of divalent metals. DNase I footprinting assays indicated that IdeR binding protects a 28-bp region containing a palindromic sequence of the fxbA promoter that was identified in primer extension assays. fxbA regulation was measured in M. smegmatis wild-type and ideR mutant strains containing fxbA promoter-lacZ fusions. These experiments confirmed that fxbA expression is negatively regulated by iron and showed that inactivation of ideR results in iron-independent expression of fxbA. However, the levels of its expression in the ideR mutant were approximately 50% lower than those in the wild-type strain under iron limitation, indicating an undefined positive role of IdeR in the regulation of fxbA.

publication date

  • June 1, 1999

Research

keywords

  • Bacterial Proteins
  • Gene Expression Regulation, Bacterial
  • Iron
  • Mycobacterium
  • Repressor Proteins
  • Transcription, Genetic

Identity

PubMed Central ID

  • PMC93806

Scopus Document Identifier

  • 0033000384

Digital Object Identifier (DOI)

  • 10.1128/JB.181.11.3402-3408.1999

PubMed ID

  • 10348851

Additional Document Info

volume

  • 181

issue

  • 11