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Cell. 2006 Apr 7;125(1):71-84.

An RNA sensor for intracellular Mg(2+).

Author information

1
Howard Hughes Medical Institute, Department of Molecular Microbiology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8230, St. Louis, MO 63110, USA.

Abstract

Most RNA molecules require Mg(2+) for their structure and enzymatic properties. Here we report the first example of an RNA serving as sensor for cytoplasmic Mg(2+). We establish that expression of the Mg(2+) transporter MgtA of Salmonella enterica serovar Typhimurium is controlled by its 5' untranslated region (5'UTR). We show that the 5'UTR of the mgtA gene can adopt different stem-loop structures depending on the Mg(2+) levels, which determine whether transcription reads through into the mgtA coding region or stops within the 5'UTR. We could recapitulate the Mg(2+)-regulated transcription using a defined in vitro transcription system with RNA polymerase as the only protein component. The initiation of mgtA transcription responds to extracytoplasmic Mg(2+) and its elongation into the coding region to cytoplasmic Mg(2+), providing a singular example in which the same ligand is sensed in different cellular compartments to regulate disparate steps in gene transcription.

PMID:
16615891
DOI:
10.1016/j.cell.2006.01.043
[Indexed for MEDLINE]
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