Cell Division Cycle Protein 40 (CDC40)

Pre-mRNA splicing occurs in two sequential transesterification steps. CDC40 is found to be essential for the catalytic step II in pre-mRNA splicing process. It is found in the spliceosome, and contains seven WD repeats, which function in protein-protein interactions. This protein has a sequence similarity to yeast Prp17 protein, which functions in two different cellular processes: pre-mRNA splicing and cell cycle progression. It suggests that this protein may play a role in cell cycle progression.The deduced 579-amino acid PRP17 protein, 36% identical to the yeast sequence, contains 7 potential C-terminal WD repeats, which function in protein-protein interactions. Western blot analysis detected a 66-kD protein that appeared later than SAP130 and was associated with the spliceosome prior to catalytic step II.