The mycobacterial iron-dependent regulator IdeR induces ferritin (bfrB) by alleviating Lsr2 repression

Kurthkoti, Krishna and Tare, Priyanka and Paitchowdhury, Rakhi and Gowthami, Vykuntham Naga and Garcia, Maria J and Colangeli, Roberto and Chatterji, Dipankar and Nagaraja, Valakunja and Rodriguez, Marcela G (2015) The mycobacterial iron-dependent regulator IdeR induces ferritin (bfrB) by alleviating Lsr2 repression. In: MOLECULAR MICROBIOLOGY, 98 (5). pp. 864-877.

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Abstract

Emerging evidence indicates that precise regulation of iron (Fe) metabolism and maintenance of Fe homeostasis in Mycobacterium tuberculosis (Mtb) are essential for its survival and proliferation in the host. IdeR is a central transcriptional regulator of Mtb genes involved in Fe metabolism. While it is well understood how IdeR functions as a repressor, how it induces transcription of a subset of its targets is still unclear. We investigated the molecular mechanism of IdeR-mediated positive regulation of bfrB, the gene encoding the major Fe-storage protein of Mtb. We found that bfrB induction by Fe required direct interaction of IdeR with a DNA sequence containing four tandem IdeR-binding boxes located upstream of the bfrB promoter. Results of in vivo and in vitro transcription assays identified a direct repressor of bfrB, the histone-like protein Lsr2. IdeR counteracted Lsr2-mediated repression in vitro, suggesting that IdeR induces bfrB transcription by antagonizing the repressor activity of Lsr2. Together, these results elucidate the main mechanism of bfrB positive regulation by IdeR and identify Lsr2 as a new factor contributing to Fe homeostasis in mycobacteria.

Item Type:	Journal Article
Publication:	MOLECULAR MICROBIOLOGY
Publisher:	WILEY-BLACKWELL
Additional Information:	Copy right for this article belongs to the WILEY-BLACKWELL, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	18 Feb 2016 05:58
Last Modified:	18 Feb 2016 05:58
URI:	http://eprints.iisc.ac.in/id/eprint/53288

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