Pre-mRNA Processing Factor 4 (PRPF4)

The removal of introns from nuclear pre-mRNAs occurs on complexes called spliceosomes, which are made up of 4 small nuclear ribonucleoprotein (snRNP) particles and an undefined number of transiently associated splicing factors. PRPF4 is 1 of several proteins that associate with U4 and U6 snRNPs.The deduced 521-amino acid protein has a calculated molecular mass of about 58.5 kD. By Western blot analysis, PRPF4 showed an apparent molecular mass of about 55 kD. PRPF4 contains 7 WD repeats that cover the entire C-terminal portion of the protein. These repeats are predicted to form a 7-fold beta propeller, like those found in the beta subunits of heterotrimeric G proteins.