Circular RNAs (circRNAs) are a sizable class of RNA that are highly expressed in the brains of mammals, but until recently, scientists were unsure of their purpose. Now, researchers led by Nikolaus Rajewsky have linked a circular RNA to brain function.
In 2013, two groundbreaking studies, one of them by the research team from this study, characterized circular RNAs for the first time. It was at this point that scientists confirmed that circRNAs were not errors– that they were instead specifically expressed, and conserved throughout evolution. The 2013 research by the Rajewsky team described Cdr1as, a circRNA that acts as a sponge for the microRNA miR-7, a small non-coding RNA molecule involved in regulating gene expression. They found Cdr1as has more than 60 binding sites for miR-7, although the purpose of the attraction was unknown.
The knockout mice also exhibited abnormal neuronal activity and disrupted neurotransmission. Practical behavioral consequences included “disrupted pre-pulse inhibition,” expressed as a poor ability to suppress the startle response despite receiving a warning. Similar disruptions in pre-pulse inhibition have been observed in humans with psychiatric diseases, who have difficulty filtering out noise that is of no consequence. Ultimately, these findings may mean new treatments for people with these kinds of psychiatric disorders.