title: PRPF4 mutations cause autosomal dominant retinitis pigmentosa.
abstract: Retinitis pigmentosa (RP), a disease characterized by progressive loss of photoreceptors, exhibits significant genetic heterogeneity. Several genes associated with U4/U6-U5 triple small nuclear ribonucleoprotein (tri-snRNP) complex of the spliceosome have been implicated in autosomal dominant RP (adRP). HPrp4, encoded by PRPF4, regulates the stability of U4/U6 di-snRNP, which is essential for continuous splicing. Here, we identified two heterozygous variants in PRPF4, including c.-114_-97del in a simplex RP patient and c.C944T (p.Pro315Leu), which co-segregates with disease phenotype in a family with adRP. Both variants were absent in 400 unrelated controls. The c.-114_-97del, predicted to affect two transcription factor binding sites, was shown to down-regulate the promoter activity of PRPF4 by a luciferase assay, and was associated with a significant reduction of PRPF4 expression in the blood cells of the patient. In fibroblasts from an affected individual with the p.Pro315Leu variant, the expression levels of several tri-snRNP components, including PRPF4 itself, were up-regulated, with altered expression pattern of SC35, a spliceosome marker. The same alterations were also observed in cells over expressing hPrp4(Pro315Leu), suggesting that they arose as a compensatory response to a compromised splicing mechanism caused by hPrp4 dysfunction. Further, over expression of hPrp4(Pro315Leu), but not hPrp4(WT), triggered systemic deformities in wild-type zebrafish embryos with the retina primarily affected, and dramatically augmented death rates in morphant embryos, in which orthologous zebrafish prpf4 gene was silenced. We conclude that mutations of PRPF4 cause RP via haploinsufficiency and dominant-negative effects, and establish PRPF4 as a new U4/U6-U5 snRNP component associated with adRP.
authors.affiliation: Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Chen
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Xunlun
authors.initials: X
authors.lastname: Sheng
authors.forename: Pancy O S
authors.initials: PO
authors.lastname: Tam
authors.forename: Kanxing
authors.initials: K
authors.lastname: Zhao
authors.forename: Xuejuan
authors.initials: X
authors.lastname: Chen
authors.forename: Weining
authors.initials: W
authors.lastname: Rong
authors.forename: Yani
authors.initials: Y
authors.lastname: Liu
authors.forename: Xiaoxing
authors.initials: X
authors.lastname: Liu
authors.forename: Xinyuan
authors.initials: X
authors.lastname: Pan
authors.forename: Li Jia
authors.initials: LJ
authors.lastname: Chen
authors.forename: Qingshun
authors.initials: Q
authors.lastname: Zhao
authors.forename: Douglas
authors.initials: D
authors.lastname: Vollrath
authors.forename: Chi Pui
authors.initials: CP
authors.lastname: Pang
authors.forename: Chen
authors.initials: C
authors.lastname: Zhao
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D002648:Child; D015536:Down-Regulation; D005260:Female; D005799:Genes, Dominant; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D010375:Pedigree; D011401:Promoter Regions, Genetic; D012174:Retinitis Pigmentosa / Q000235:genetics* / Q000378:metabolism; D017414:Ribonucleoprotein, U4-U6 Small Nuclear / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D055815:Young Adult
chemical_list: C489982:PRPF4 protein, human; D017414:Ribonucleoprotein, U4-U6 Small Nuclear