Answers are grounded in this paper and cite their sources.
We isolated a mouse genomic clone that hybridized with small RNA present in the cytoplasm of the brain. The RNA was about 150 nucleotides long. This RNA seemed to be specific to the brain, since it was not found in the liver or kidney. The clone DNA contained a sequence homologous to 82-nucleotide "identifier" core sequence of cDNA clones of rat. The sequence contained a split promoter for RNA polymerase III and was flanked by a 12-nucleotide direct repeat (ATAAATAATTTA).
No takes yet. Share an insight, caveat, or question.
Anzai et al. (1986) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: