FIGURE 2.

Schematic diagram illustrating the structures of spliceosome complex B and tri-snRNP. (A) Composition of complex B; (B) cryo-EM structure of pre-catalytic spliceosome complex B with RP-linked PRPFs highlighted. The pre-mRNA, U4, and U6 snRNAs are colored brown, magenta, and orange, respectively. Six PRPFs, which are core components of tri-snRNP, are labelled and color-coded. Residues mutated in RP are shown as red spheres. The PRPF8 Jab1 domain is labelled. The image was created using PyMol (DeLano, 2002).