An RNA Sensor for Intracellular Mg2+

Michael J. Cromie, Yixin Shi, Tammy Latifi, Eduardo A. Groisman

Research output: Contribution to journalArticlepeer-review

261 Scopus citations


Most RNA molecules require Mg2+ for their structure and enzymatic properties. Here we report the first example of an RNA serving as sensor for cytoplasmic Mg2+. We establish that expression of the Mg2+ 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 Mg2+ levels, which determine whether transcription reads through into the mgtA coding region or stops within the 5′UTR. We could recapitulate the Mg2+-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 Mg2+ and its elongation into the coding region to cytoplasmic Mg2+, providing a singular example in which the same ligand is sensed in different cellular compartments to regulate disparate steps in gene transcription.

Original languageEnglish (US)
Pages (from-to)71-84
Number of pages14
Issue number1
StatePublished - Apr 7 2006
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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