Pre-mRNA splicing occurs in 2 sequential transesterification steps. The protein encoded by this gene 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 the yeast splicing factor Prp18. [provided by RefSeq, Jul 2008].