Ligation of RNA pool to universal adaptor in CircLig protocol. (A) Schematic of the ligation reaction. (B) 40 ng RNA pool was ligated in the presence of excess universal adaptor with either trRnl2 K227Q or Mth K97A as described in the Methods. RNA was precipitated and separated on a 15% acrylamide gel. (1) Universal adaptor (2) fragment pool (3) ligated fragments.