| Sm core assembly and 3 end processing of pre U1 snRNA |
| pre U1 snRNP import and U1 snRNP formation |
| Spliceosome assembly (E and A complex formation) |
| U4/U6-U5 snRNP fomation |
| Spliceosome assembly (B complex formation) |
| spliceosome activation |
| Spliceosome catalysis (branching) |
| Spliceosome catalysis (exon ligation) |
| Spliceosome disassembly |
| mRNA export to the cytoplasm |
