·RNA-based thermosensors can sense different temperatures
We designed four different types of RNA-based thermosensors, including heat-inducible RNA-based thermosensor, heat-repressible RNA-based thermosensor, cold-inducible RNA-based thermosensor and cold-repressible RNA-based thermosensor. We have designed more than 200 different thermosensors, and constructed their measurement device.
After the experiments, we got some inspiring results. As figure 1 shows, heat-inducible RNA-based thermosensors' activities increase at elevated temperature. Heat-repressible RNA-based thermosensors' activities decrease with the increasement of temperature. Besides, cold-inducibe RNA-based thermosensors show lower sensing temperature range than heat-repressible RNA thermosensor, whose intensity decrease sharply from 15 to 20℃. And cold-repressible RNA-based thermosensors' activity decrease with decreasing temperature even below 29℃.
Figure 1. Heat map of four different types of RNA-based thermosensors. Rows represent activity levels of different thermosensors. These values are normalized using the Fluorescence/Abs600 of positive control. (A) includes 48 heat-inducible RNA-based thermosensors' activities at 29, 31, 35, 37, 39 and 42℃. (B) includes 22 heat-repressible RNA-based thermosensors' activities at 29, 37 and 42℃. (C) includes 10 cold-repressible RNA-based thermosensors' activities at 15, 25, 29, 35 and 37℃. (D) includes 8 cold-inducible RNA-based thermosensors' activities at 15, 20, 25℃.
·Features of RNA-based thermosensors can be computed by using fitted curve
In order to get the melting temperature, intensity and sensitivity of the thermosensors, we fitted a curve to reflect the relationship between the change of temperature and the expression intensity of thermosensors (Figure 2).
Figure 2. The fitted curve of BBa_K2541029. The black dash line is the tangent line at melting temperature. The intersection of the upper gray dash line and curve represents the stem-loop structures of thermosensors are all destroyed. The intersection of the medial gray dash line and curve represents a 50% switch in expression occurs, and it is defined as melting temperature. The intersection of lower gray dash line and curve represents the stem-loop structure of thermosensors all exsit.
Table 1 shows the features of all the heat-inducible thermosensors we obtained from the fitting curve.
Table 1. Features of the heat-inducible RNA-based thermosensors
These features point to the diversity in thermosensor response. These thermosensors' melting temperatures range 33 to 55℃, with different relative intensity and sensitivity.
·SynRT toolkit is developed and updated to version 3.0
Based on these data, we classified these thermosensors by melting temperature, relative intensity and sensitivity, and developed a search engine -- SynRT Explorer. You can visit our Search Engine page to use it.