Small Nuclear Ribonucleoprotein 40kDa (SNRNP40)

SPF38 is a component of the U5 small nuclear ribonucleoprotein (snRNP) particle. The U5 snRNP is part of the spliceosome, a multiprotein complex involved in the removal of introns from nuclear pre-mRNAs.The deduced 357-amino acid protein has a calculated molecular mass of 39.3 kD. Except for 63 N-terminal amino acids, the entire SPF38 protein is made up of 7 WD40 repeats. Highly homologous protein sequences were found in rat, mouse, fruit fly, and plant EST databases.SPF38 has a calculated molecular mass of 38.4 kD and shows an apparent molecular mass of 30 kD in 2-dimensional gels.By sedimentation analysis, radioimmunoprecipitations, and Far Western (overlay) analysis, Achsel et al. (1998) determined that SPF38 interacts directly with PRPF8.