Transcription yields a continuous supply of some types of pri-miRNA transcripts, capped and polyadenylated. hnRNPs are hypothesized to shape the pri-miRNA into linear and hairpin sections. A signaling system somehow recruits and activates unknown factors that select particular pre-miRNA hairpins on a particular pri-miRNA for excision and processing in the miRNA pathway. We hypothesize that this system might include a binding motif. RNASEN and DGCR8 are products of genes 29102 and 54487.