title: Knockdown of the zebrafish ortholog of the retinitis pigmentosa 2 (RP2) gene results in retinal degeneration.
abstract: OBJECTIVE
  The authors investigated the expression and function of the zebrafish ortholog of the retinitis pigmentosa 2 (RP2) gene.
  
  
  METHODS
  Zebrafish RP2 (ZFRP2) cDNA was isolated from adult eye mRNA by reverse transcription-polymerase chain reaction (RT-PCR). Gene expression was examined by RT-PCR. The deduced peptide sequence was aligned with RP2 orthologues from different species. Translational suppression (knockdown) of zebrafish RP2 was carried out by antisense morpholino-injection. The phenotype of ZFRP2 knockdown morphants was characterized by immunohistology and histology. Human wild-type and mutant RP2 mRNAs were coinjected with ZFRP2 morpholinos to test whether human RP2 mRNA could rescue ZFRP2 knockdown phenotypes.
  
  
  RESULTS
  ZFRP2 encodes a protein of 376 amino acids containing an N-terminal tubulin folding cofactor C-like domain and a C-terminal nucleoside diphosphate kinase-like domain. It shares 63% to 65% amino acid identity with human, mouse and bovine RP2. RP2 is expressed at the earliest stages of zebrafish development and persists into adulthood. Knockdown of RP2 in zebrafish causes a curved body axis and small eye phenotype, associated with increased cell death throughout the retina. Human wild-type RP2 mRNA could rescue the body curvature phenotype of ZFRP2 morphants, and the eye size of the resultant morphants was significantly increased over that of morphants in which ZFRP2 had been depleted.
  
  
  CONCLUSIONS
  Zebrafish RP2 is widely expressed throughout development. ZFRP2 knockdown caused retinal degeneration in zebrafish. Human RP2 could partially rescue the small eye phenotype of ZFRP2 morphants.
authors.affiliation: Department of Biological and Biomedical Sciences, Glasgow Caledonian University, United Kingdom. xinhua.shu@gcu.ac.uk
authors.forename: Xinhua
authors.initials: X
authors.lastname: Shu
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zeng
authors.forename: Philippe
authors.initials: P
authors.lastname: Gautier
authors.forename: Alan
authors.initials: A
authors.lastname: Lennon
authors.forename: Milica
authors.initials: M
authors.lastname: Gakovic
authors.forename: Michael E
authors.initials: ME
authors.lastname: Cheetham
authors.forename: E Elizabeth
authors.initials: EE
authors.lastname: Patton
authors.forename: Alan F
authors.initials: AF
authors.lastname: Wright
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D001483:Base Sequence; D002417:Cattle; D003001:Cloning, Molecular; D005136:Eye Proteins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D020868:Gene Silencing / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008969:Molecular Sequence Data; D010641:Phenotype; D012333:RNA, Messenger / Q000235:genetics; D012160:Retina / Q000196:embryology / Q000378:metabolism; D012162:Retinal Degeneration / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D005136:Eye Proteins; D012333:RNA, Messenger; C559526:RP2 protein, zebrafish; D029961:Zebrafish Proteins