The 20kD protein of human [U4/U6.U5] tri-snRNPs is a novel cyclophilin that forms a complex with the U4/U6-specific 60kD and 90kD proteins.
S Teigelkamp, T Achsel, C Mundt, S F Göthel, U Cronshagen, W S Lane, M Marahiel, and R Lührmann
RNA. 1998 February; 4(2): 127–141. PMCID: PMC1369602