Riboswitch

[1][2][3][4] Thus, an mRNA that contains a riboswitch is directly involved in regulating its own activity, in response to the concentrations of its effector molecule.

The original definition of the term "riboswitch" specified that they directly sense small-molecule metabolite concentrations.

Prior to the discovery of riboswitches, the mechanism by which some genes involved in multiple metabolic pathways were regulated remained mysterious.

Accumulating evidence increasingly suggested the then-unprecedented idea that the mRNAs involved might bind metabolites directly, to affect their own regulation.

These data included conserved RNA secondary structures often found in the untranslated regions (UTRs) of the relevant genes and the success of procedures to create artificial small molecule-binding RNAs called aptamers.

Bioinformatics has played a role in more recent discoveries, with increasing automation of the basic comparative genomics strategy.

Riboswitches demonstrate that naturally occurring RNA can bind small molecules specifically, a capability that many previously believed was the domain of proteins or artificially constructed RNAs called aptamers.

It has been suggested that some riboswitches might represent ancient regulatory systems, or even remnants of RNA-world ribozymes whose bindings domains are conserved.