RNA pH METER
The RNA pH-meter is a new part that initiates translation only at alkaline conditions. It was first observed in Escherichia coli, as the 5’UTR preceding the alx locus, termed the SraF gene, having two stable RNA structures. The first structure, the N structure, is formed at neutral pH and the second structure termed the H structure is formed at higher pH. In the N structure, multiple stem loops occlude the Shine Dalgarno sequence thereby inhibiting translation whereas in the H structure the Shine Dalgarno sequence is exposed to the incoming ribosome thereby facilitating translation. Hence, this way, the SraF 5’UTR can be made to function as a pH sensitive translational riboswitch that induces translation in alkaline conditions. Therefore, placing a protein coding sequence downstream of the 5’UTR leads to pH sensitive translation of said protein.
Characterization studies can be found here.
RNA pH Meter
- Nechooshtan, G., Elgrably-Weiss, M., Sheaffer, A.,Westhof, E., & Altuvia, S. A pH-responsive riboregulator.Genes Dev. 23, 2650–2662 (2009).
- Nechooshtan, G., Elgrably-Weiss, M., & Altuvia, S.Changes in transcriptional pausing modify the folding dynamics of the pH-responsive RNA element. Nucleic Acids research. 42(1), 622-630 (2013)
- Bingham, R., Karen, H., Joan S. Alkaline induction of a Novel Gene Locus, alx, in Escherichia coli. Journal of Bacteriology. 172(4), 2184-2186(1990)