The Magnesium-responsive RNA element (Mg_sensor) regulates the expression of the mgtA gene in Enterobacteria. The product of mgtA is a magnesium transporter, and the occurrence of mgtA together with other magnesium transporter genes within the same organism suggests that the maintenance of Mg2+ concentration is a highly regulated process that must be carefully monitored to avoid building up of toxic metals [11972791]. Mg2+ is the most abundant divalent cation inside cells and serves as a cofactor in a wide variety of cellular processes including ATP-mediated enzymatic reactions and ribosome stability [3056314, 17381304]. more

The mechanism of Mg_sensor is still unclear, although it has been suggested that the mgtA transcript may be targeted for RNase E-mediated degradation under high cellular Mg2+ concentration [18248433].