Pre-mRNA Processing Factor 31 (PRPF31)

PRPF31 is recruited to introns following the attachment of U4 and U6 RNAs and the 15.5K protein. The addition of PRPF31 is crucial for the transition of the spliceosomal complex to the activated state. PRPF31 encodes a putative 499-amino acid protein that is 20% and 38% identical to its S. cerevisiae and S. pombe homologs, respectively. The level of sequence identity to the yeast genes indicates that PRPF31 is likely to be involved in pre-mRNA splicing. PRPF31 and its homologs all contain a region homologous to Nop, a putative snoRNA-binding domain. In yeast Prp31, the Nop domain is thought to mediate protein-RNA interactions required for spliceosome assembly. PRPF31 also has putative nuclear localization signals in its medial region, providing further evidence for a nuclear role.