An RNA sensor for intracellular Mg(2+)

Cell. 2006 Apr 7;125(1):71-84. doi: 10.1016/j.cell.2006.01.043.

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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 5' Untranslated Regions / chemistry*
  • 5' Untranslated Regions / genetics
  • 5' Untranslated Regions / metabolism
  • Adenosine Triphosphatases / genetics
  • Bacterial Proteins / genetics
  • Biosensing Techniques / methods*
  • Conserved Sequence / genetics
  • Cytoplasm / chemistry
  • Gene Expression Regulation, Bacterial
  • Magnesium / analysis*
  • Magnesium / metabolism*
  • Magnesium / pharmacology
  • Membrane Transport Proteins / genetics
  • Models, Genetic
  • Mutation / genetics
  • Nucleic Acid Conformation* / drug effects
  • Open Reading Frames / genetics
  • Phylogeny
  • Promoter Regions, Genetic / genetics
  • RNA, Bacterial / chemistry*
  • RNA, Bacterial / genetics
  • RNA, Bacterial / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Regulatory Sequences, Nucleic Acid / genetics
  • Ribonucleases / metabolism
  • Terminator Regions, Genetic / genetics
  • Transcription, Genetic / drug effects

Substances

  • 5' Untranslated Regions
  • Bacterial Proteins
  • Membrane Transport Proteins
  • RNA, Bacterial
  • RNA, Messenger
  • Ribonucleases
  • Adenosine Triphosphatases
  • MgtA protein, bacteria
  • Magnesium