The spliceosome of Trypanosomes compared to that of H. sapiens. Unlike the spliceosome of most eukaryotes the SM protein complex of Trypanosomes contains two unique Sm proteins SM15K and SM16.5K. The Sm core associates with U2 and not U1 in Trypanosomes. The human stem loop RNA separating U2A and U1 is absent in Trypanosomes. The unique SM proteins are required for the correct assembly of U2A in Trypanosomes. The unique structure of the Trypanosome spliceosome seems to play a role in Trans-splicing, which is the dominant form of mRNA splicing in Trypanosomes.