Coronavirus frameshifting stimulation element
In molecular biology, the coronavirus frameshifting stimulation element is a conserved stem-loop of RNA found in coronaviruses that can promote ribosomal frameshifting. Such RNA molecules interact with a downstream region to form a pseudoknot structure; the region varies according to the virus but pseudoknot formation is known to stimulate frameshifting.
Source: Wikipedia — Coronavirus frameshifting stimulation element (CC BY-SA 4.0)