YkoK leader
| ykoK leader | |
|---|---|
 | |
| Predicted secondary structure and sequence conservation of ykoK | |
| Identifiers | |
| Symbol | ykoK |
| Rfam | RF00380 |
| Other data | |
| RNA type | Cis-reg |
| Domain(s) | Bacteria |
| SO | 0000233 |
The Ykok leader or M-box is a Mg2+-sensing RNA structure that controls the expression of Magnesium ion transport proteins in bacteria. It is a distinct structure to the Magnesium responsive RNA element.
The Ykok leader was originally described as a conserved sequence with potential riboswitch function found upstream of the B. subtilis ykoK gene and genes with related functions in other bacteria.[2] Examples of the conserved M-box RNA structure occur upstream of each of the three major families of Mg2+ transporters (CorA, MgtE and MgtA/MgtB) in various bacterial species.[1]
The molecular structure of the M-box example upstream of the B. subtilis ykoK gene includes six bound Mg2+ ions. Biochemical studies indicate that this M-Box RNA compacts in the presence of Mg2+ and other divalent ions. This folding process appears to disrupt an antiterminator structure, and thereby allow a transcription terminator structure to form. As expected from this model, B. subtilis cells repress expression of a downstream reporter gene when grown in the presence of Mg2+. Therefore, the M-box appears to function as a genetic "off" switch that is important for maintaining Mg2+ homeostasis in bacteria.
References
- ↑ 1.0 1.1 Dann CE, Wakeman CA, Sieling CL, Baker SC, Irnov I, Winkler WC (2007). "Structure and mechanism of a metal-sensing regulatory RNA.". Cell 130 (5): 878–92. doi:10.1016/j.cell.2007.06.051. PMID 17803910.
- ↑ Barrick, JE; Corbino KA, Winkler WC, Nahvi A, Mandal M, Collins J, Lee M, Roth A, Sudarsan N, Jona I, Wickiser JK, Breaker RR (2004). "New RNA motifs suggest an expanded scope for riboswitches in bacterial genetic control". Proc Natl Acad Sci USA 101 (17): 6421–6426. doi:10.1073/pnas.0308014101. PMC 404060. PMID 15096624.