title: Targeted mutation of the gene encoding prion protein in zebrafish reveals a conserved role in neuron excitability.
abstract: The function of the cellular prion protein (PrP(C)) in healthy brains remains poorly understood, in part because Prnp knockout mice are viable. On the other hand, transient knockdown of Prnp homologs in zebrafish (including two paralogs, prp1 and prp2) has suggested that PrP(C) is required for CNS development, cell adhesion, and neuroprotection. It has been argued that zebrafish Prp2 is most similar to mammalian PrP(C), yet it has remained intransigent to the most thorough confirmations of reagent specificity during knockdown. Thus we investigated the role of prp2 using targeted gene disruption via zinc finger nucleases. Prp2(-/-) zebrafish were viable and did not display overt developmental phenotypes. Back-crossing female prp2(-/-) fish ruled out a role for maternal mRNA contributions. Prp2(-/-) larvae were found to have increased seizure-like behavior following exposure to the convulsant pentylenetetrazol (PTZ), as compared to wild type fish. In situ recordings from intact hindbrains demonstrated that prp2 regulates closing of N-Methyl-d-aspartate (NMDA) receptors, concomitant with neuroprotection during glutamate excitotoxicity. Overall, the knockout of Prp2 function in zebrafish independently confirmed hypothesized roles for PrP, identifying deeply conserved functions in post-developmental regulation of neuron excitability that are consequential to the etiology of prion and Alzheimer diseases.
authors.affiliation: Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Valerie C
authors.initials: VC
authors.lastname: Fleisch
authors.forename: Patricia L A
authors.initials: PL
authors.lastname: Leighton
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Laura M
authors.initials: LM
authors.lastname: Pillay
authors.forename: R Gary
authors.initials: RG
authors.lastname: Ritzel
authors.forename: Ganive
authors.initials: G
authors.lastname: Bhinder
authors.forename: Birbickram
authors.initials: B
authors.lastname: Roy
authors.forename: Keith B
authors.initials: KB
authors.lastname: Tierney
authors.forename: Declan W
authors.initials: DW
authors.lastname: Ali
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Waskiewicz
authors.forename: W Ted
authors.initials: WT
authors.lastname: Allison
mesh_terms: D000367:Age Factors; D000818:Animals; D030801:Animals, Genetically Modified; D004195:Disease Models, Animal; D004827:Epilepsy / Q000139:chemically induced / Q000503:physiopathology; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D015723:Gene Library; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007814:Larva; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics*; D009474:Neurons / Q000378:metabolism*; D010433:Pentylenetetrazole / Q000633:toxicity; D010641:Phenotype; D011328:Prions / Q000235:genetics*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D015027:Zebrafish / Q000235:genetics / Q000254:growth & development; D016335:Zinc Fingers / Q000235:genetics
chemical_list: D011328:Prions; D016194:Receptors, N-Methyl-D-Aspartate; D049452:Green Fluorescent Proteins; D010433:Pentylenetetrazole