Summary:
According to microarray analysis, the "mannosyl-d-glycerate regulator," MngR, regulates only two genes, mngA and mngB, involved in 2-O-α-mannosyl-D-glycerate utilization [2]. This regulator also autoregulates its own synthesis [1].
Previously, MngR, also called FarR, for fatty acyl-responsive regulator, had been proposed to regulate genes involved in the citric acid cycle in response to fatty acids, which release MngR from its DNA-binding site [1]. However, when it was found that this protein only regulates two genes, the suggestion was rejected and it was proposed that probably high concentrations of fatty acids could degrade the protein instead of it binding to the regulator [2].
MngR belongs to the GntR family of transcriptional regulators and has a helix-turn-helix motif in the N-terminal domain and a UbiC transcription regulator-associated domain that is predicted to be a sensor for small molecules.
This domain is found in proteins such as UbiC from
Escherichia coli, TreR from
Bacillus subtilis, and HutC from
Pseudomonas aeruginosa [4].
The
mntR gene is transcribed divergently from the
mngAB operon. They share a regulatory region that contains two sites of 21 bp each, one with two direct repeat sequences of 10 bp that are bound by MngR
[1].
mngR shows differential codon adaptation, resulting in differential translation efficiency signatures, in thermophilic microbes. It was therefore predicted to play a role in the heat shock response. An
mngR deletion mutant was shown to be more sensitive than wild-type specifically to heat shock, but not other stresses
[5].
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