Revision as of 13:52, 7 October 2018

Cold-repressible RNA-based thermosensor-1

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

Usage and Biology

RNA-based temperature sensing is common in bacteria that live in fluctuating environments. Most naturally-occurring RNA thermosensors have long sequences and complicated sencondary structure. Here, we designed short, cold-repressible RNA thermosensors,which will form a stem-loop upstream Shine–Dalgarno (SD) sequence. These thermosensors contain a double-strand RNA cleavage site for RNase III, an enzyme native to Escherichia coli and many other organisms, in the 5' untranslated region of the target gene. At low temperatures, the mRNA stem-loop is stable to expose the RNase III cleavage site and the transcript will be degraded. At elevated temperatures, the stem-loop will unfold and translation will occur unhindered. These short, modular cold-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_K2541201) and sfGFP(BBa_K2541400). We measured the sfGFP expression to get the state of the cold-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