Revision as of 11:03, 7 October 2018

Heat-repressible RNA-based thermosensor-22

A RNA thermosensor that can be used for temperature sensitive post-transcriptional regulation which is based on the change of RNA sencondary structure. The heat-repressible RNA thermosensors can repress translation of downstream genes at high temperatures.

Usage and Biology

RNA-based temperature sensing is common in bacteria that live in fluctuating environments. Most naturally-occurring RNA thermosensors are heat-inducible, have long sequences, and function by sequestering the ribosome binding site in a stem-loop structure at lower temperatures. Here, we designed short, heat-repressible RNA thermosensors. These thermosensors contain a single-strand RNA cleavage site for RNase E, an enzyme native to Escherichia coli and many other organisms, in the 5' untranslated region of the target gene. At low temperatures, the cleavage site is sequestered in a stem-loop, and gene expression is unobstructed. At elevated temperatures, the stem-loop unfolds, allowing for mRNA degradation and turning off expression. These short, modular heat-repressible RNA thermosensors can be applied to the construction of complex genetic circuits, facilitating rational reprogramming of cellular processes for synthetic biology applications.

Characterization

The thermosensor is constructed on the pSB1C3 vector by goldengate assembly. As shown below, the measurement device is composed of Anderson promotor (BBa_J23104), thermosensor (BBa_K2541122) and sfGFP(BBa_K2541400). We measured the sfGFP expression to get the state of the heat-repressible RNA thermosensor at different temperatures.

As shown in the figure, the thermosensor is "off" at [ ]. Our data show that efficient RNA thermosensors can be built from a single small RNA stem-loop structure masking the ribosome binding site, thus providing useful RNA-based toolkit for the regulation of gene expression.

Sequence and Features