ribozymes
 There are two predominate methods for harnessing cis-acting
regulatory RNAs for genetic control: transcription attenuation and
translation inhibition. However, an alternate mechanism is used by a
glucosamine-6-phosphate (GlcN6P)-sensing RNA located upstream of the glmS gene.
Prior studies revealed that GlcN6P promoted an autocatalytic,
site-specific cleavage event near the 5' terminus in vitro, thus
demonstrating that the RNA is a natural metabolite-responsive ribozyme.
More recently, we revealed that ribozyme self-cleavage is coupled to
mRNA destabilization. Specifically, our data showed that a change in
molecular identity at the 5' terminus is the rate-limiting step for
degradation of the downstream mRNA upon ribozyme self-cleavage.
Moreover, we have identified the RNase enzyme that is required for mRNA
destabilization. We have chosen to investigate this particular mechanism
in detail because it is likely to provide key insights into the general
‘rules’ of bacterial mRNA degradation pathways. Also, we anticipate
these studies to reveal underlying principles that could be useful for
the design of synthetic signal-responsive ribozymes.
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