Affiliation:
1. Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
2. Center for Network Systems Biology, Boston University, Boston, MA 02118, USA
Abstract
ABSTRACT
Blindness associated with Usher syndrome type 1 (USH1) is typically characterized as rod photoreceptor degeneration, followed by secondary loss of cones. The mechanisms leading to blindness are unknown because most genetic mouse models only recapitulate auditory defects. We generated zebrafish mutants for one of the USH1 genes, protocadherin-15b (pcdh15b), a putative cell adhesion molecule. Zebrafish Pcdh15 is expressed exclusively in photoreceptors within calyceal processes (CPs), at the base of the outer segment (OS) and within the synapse. In our mutants, rod and cone photoreceptor integrity is compromised, with early and progressively worsening abnormal OS disc growth and detachment, in part due to weakening CP contacts. These effects were attenuated or exacerbated by growth in dark and bright-light conditions, respectively. We also describe novel evidence for structural defects in synapses of pcdh15b mutant photoreceptors. Cell death does not accompany these defects at early stages, suggesting that photoreceptor structural defects, rather than overt cell loss, may underlie vision deficits. Thus, we present the first genetic animal model of a PCDH15-associated retinopathy that can be used to understand the aetiology of blindness in USH1.
This article has an associated First Person interview with the first author of the paper.
Funder
Fighting Blindness Canada
Natural Sciences and Engineering Research Council of Canada
University of Toronto
Publisher
The Company of Biologists
Subject
General Biochemistry, Genetics and Molecular Biology,Immunology and Microbiology (miscellaneous),Medicine (miscellaneous),Neuroscience (miscellaneous)
Cited by
15 articles.
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