Recent Articles

Rodriguez GM, Voskuil MI, Gold B, Schoolnik GK, Smith I.
ideR, An essential gene in mycobacterium tuberculosis: role of IdeR iniron-dependent gene expression, iron metabolism, and oxidative stress response.
Infect Immun 2002 Jul;70(7):3371-81
PMID: 12065475

The mycobacterial IdeR protein is a metal-dependent regulator of the DtxR
(diphtheria toxin repressor) family. In the presence of iron, it binds to a
specific DNA sequence in the promoter regions of the genes that it regulates,
thus controlling their transcription. In this study, we provide evidence that
ideR is an essential gene in Mycobacterium tuberculosis. ideR cannot normally be
disrupted in this mycobacterium in the absence of a second functional copy of
the gene. However, a rare ideR mutant was obtained in which the lethal effects
of ideR inactivation were alleviated by a second-site suppressor mutation and
which exhibited restricted iron assimilation capacity. Studies of this strain
and a derivative in which IdeR expression was restored allowed us to identify
phenotypic effects resulting from ideR inactivation. Using DNA microarrays, the
iron-dependent transcriptional profiles of the wild-type, ideR mutant, and
ideR-complemented mutant strains were analyzed, and the genes regulated by iron
and IdeR were identified. These genes encode a variety of proteins, including
putative transporters, proteins involved in siderophore synthesis and iron
storage, members of the PE/PPE family, a membrane protein involved in virulence,
transcriptional regulators, and enzymes involved in lipid metabolism.