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