 The U4/U6 snRNP contains 15.5-kDa protein.The 15.5-kDa protein also exists in a ribonucleoprotein complex that binds the U3 box B/C motif.The 15.5-kDa protein also exists as one of the four core proteins of the C/D small nucleolar ribonucleoprotein that mediates methylation of pre-ribosomal RNAs.