Knocking DownSnrnp200Initiates Demorphogenesis of Rod Photoreceptors in Zebrafish

Yuan Liu,Chen Zhao,Jonathan P Staley,Xue Chen,Bing Qin,Kanxing Zhao,Qingshun Zhao

doi:10.1155/2015/816329

Abstract

Purpose. The small nuclear ribonucleoprotein 200 kDa (SNRNP200) gene is a fundamental component for precursor message RNA (pre-mRNA) splicing and has been implicated in the etiology of autosomal dominant retinitis pigmentosa (adRP). This study aims to determine the consequences of knocking down Snrnp200 in zebrafish. Methods. Expression of the Snrnp200 transcript in zebrafish was determined via whole mount in situ hybridization. Morpholino oligonucleotide (MO) aiming to knock down the expression of Snrnp200 was injected into zebrafish embryos, followed by analyses of aberrant splicing and expression of the U4/U6-U5 tri-small nuclear ribonucleoproteins (snRNPs) components and retina-specific transcripts. Systemic changes and retinal phenotypes were further characterized by histological study and immunofluorescence staining. Results. Snrnp200 was ubiquitously expressed in zebrafish. Knocking down Snrnp200 in zebrafish triggered aberrant splicing of the cbln1 gene, upregulation of other U4/U6-U5 tri-snRNP components, and downregulation of a panel of retina-specific transcripts. Systemic defects were found correlated with knockdown of Snrnp200 in zebrafish. Only demorphogenesis of rod photoreceptors was detected in the initial stage, mimicking the disease characteristics of RP. Conclusions. We conclude that knocking down Snrnp200 in zebrafish could alter regular splicing and expression of a panel of genes, which may eventually trigger rod defects.

Highlights

Retinitis pigmentosa (RP (MIM 268000)) is the most common form of inherited retinal dystrophies (IRDs) with a prevalence ranging from 1/3500 to 1/5000 among different populations [1,2,3]
We for the first time used a zebrafish model to characterize the retinal phenotypes and mRNA metabolism induced by knockdown of Snrnp200
Similar to findings in zebrafish with sart3, prpf31, or prpf4 knocked down [12, 14, 23], upregulation of other U4/U6-U5 tri-snRNP components was detected in Snrnp200 morphants suggesting compensatory responses of other splicing components

Summary

Introduction

Retinitis pigmentosa (RP (MIM 268000)) is the most common form of inherited retinal dystrophies (IRDs) with a prevalence ranging from 1/3500 to 1/5000 among different populations [1,2,3]. RP presents significant clinical and genetic heterogeneities [4]. In the disease course of RP, rod photoreceptors will initially be affected followed by degeneration of cone photoreceptors and retinal pigment epithelium (RPE). The clinical hallmarks of RP include initial symptom of nyctalopia, subsequent constricted visual fields (VFs), and eventual loss of central vision. 24 were autosomal dominant RP (adRP) relevant genes and they include seven ubiquitously expressed precursor messenger RNA (pre-mRNA) splicing genes, namely, PRPF8 (MIM 607300) [5], PRPF31 (MIM 606419) [6], PRPF3 (MIM 607331) [7], PIM1-associated protein (RP9 (MIM 607331)) [8], small nuclear ribonucleoprotein 200 kDa (SNRNP200 (MIM 601664)) [9, 10], PRPF6 (MIM 613979) [11], and PRPF4 (MIM 607795) [12]

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Conclusion