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.