Brain cytoplasmic RNA 1 is a protein that in humans is encoded by the BCYRN1 gene.
This gene, which encodes a neural small non-messenger RNA, is a member of the family of interspersed repetitive DNA, and its product represents an example of a primate tissue-specific RNA polymerase III transcript. The RNA sequence is divided into three domains: a 5' portion homologous to the Alu Lm, a central adenosine-rich region, and the terminal 43-nt nonrepetitive domain. It is believed that this gene was retropositionally generated and recruited into a function regulating dendritic protein biosynthesis. At least two pseudogenes of this gene have been identified.