This domain is found in U4/U6 and U4/U5/U6-small nuclear ribonucleoprotein Prp3, part of the tri-RNA complex that form the spliceosome. Prp3 plays a key role in the recognition of the snRNA duplex. The pre-mRNA processing factor 3 (PRP3) domain, responsible for the binding to stem II of the snRNA duplex, is highly conserved among eukaryotes and is found N-terminal to Pfam:PF06544 [3,4]. The human PRP3 has been implicated in autosomal retinitis pigmentosa [2].

1: Functional and structural characterization of the prp3 binding domain of the yeast prp4 splicing factor. Ayadi L, Callebaut I, Saguez C, Villa T, Mornon JP, Banroques J; J Mol Biol. 1998;284:673-687. PMID:9826507

2: Mutations in HPRP3, a third member of pre-mRNA splicing factor genes, implicated in autosomal dominant retinitis pigmentosa. Chakarova CF, Hims MM, Bolz H, Abu-Safieh L, Patel RJ, Papaioannou MG, Inglehearn CF, Keen TJ, Willis C, Moore AT, Rosenberg T, Webster AR, Bird AC, Gal A, Hunt D, Vithana EN, Bhattacharya SS; Hum Mol Genet. 2002;11:87-92. PMID:11773002

3: A composite double-/single-stranded RNA-binding region in protein Prp3 supports tri-snRNP stability and splicing. Liu S, Mozaffari-Jovin S, Wollenhaupt J, Santos KF, Theuser M, Dunin-Horkawicz S, Fabrizio P, Bujnicki JM, Luhrmann R, Wahl MC; Elife. 2015;4:e07320. PMID:26161500

4: The 3.8 A structure of the U4/U6.U5 tri-snRNP: Insights into spliceosome assembly and catalysis. Wan R, Yan C, Bai R, Wang L, Huang M, Wong CC, Shi Y; Science. 2016;351:466-475. PMID:26743623