Dicer processes dsRNA into fragments of size:
Dicer is multidomain RNase III endoribonuclease harboring N-terminal helicase, DUF283, PAZ, two RNase III domains, dsRNA-binding domain measuring distance from termini. Dicer cleaves long double-stranded RNA including viral intermediates and endogenous hairpin precursors into 21-23 nucleotide short interfering RNAs or microRNA duplexes bearing characteristic 2-nucleotide 3' overhangs, 5' monophosphate, 3' hydroxyl groups. Size determination relies on helical ruler mechanism positioning catalytic centers approximately two helical turns apart. Human Dicer partners with TRBP, fission yeast Dcr1 p
Ref: Lodish et al., Molecular Cell Biology, 9th ed., Chapter 10: Dicer Processing into 21–23 nt Fragments
