ZFIN ID: ZDB-PUB-151125-15
The zebrafish pinball wizard gene encodes WRB, a tail-anchored-protein receptor essential for inner-ear hair cells and retinal photoreceptors
Lin, S.Y., Vollrath, M.A., Mangosing, S., Shen, J., Cardenas, E., Corey, D.P.
Date: 2016
Source: The Journal of physiology   594(4): 895-914 (Journal)
Registered Authors: Lin, Shuh-Yow
Keywords: none
MeSH Terms:
  • Amino Acid Sequence
  • Animals
  • Hair Cells, Auditory/metabolism*
  • Hair Cells, Auditory/physiology
  • Molecular Sequence Data
  • Photoreceptor Cells/metabolism*
  • Photoreceptor Cells/physiology
  • Qa-SNARE Proteins/genetics
  • Qa-SNARE Proteins/metabolism
  • R-SNARE Proteins/genetics
  • R-SNARE Proteins/metabolism
  • Synaptic Transmission
  • Synaptic Vesicles/metabolism
  • Zebrafish
PubMed: 26593130 Full text @ J. Physiol.
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ABSTRACT
In a large-scale zebrafish insertional mutagenesis screen, we identified the pinball wizard (pwi) line which displays a deafness and blindness phenotype. Although the gross morphology and structure of the pwi larval inner ear was near normal, acoustic startle stimuli evoked smaller postsynaptic responses in afferent neurons which rapidly fatigued. In the retina, similarly, an abnormal electroretinogram suggested reduced transmission at the photoreceptor ribbon synapse. A functional deficit in these specialized synapses was further supported by reduction of synaptic marker proteins Rab3 and CSP/Dnajc5 in hair cells and photoreceptors, as well as by a reduction of the number of both ribbons and vesicles surrounding the ribbons in hair cells. The pwi gene encodes a homolog of the yeast Get1 and human WRB proteins, which are receptors for membrane insertion of tail-anchored (TA) proteins. We identified more than 100 TA proteins expressed in hair cells, including many synaptic proteins. The expression of synaptobrevin and syntaxin 3, TA proteins essential for vesicle fusion, was reduced in the synaptic layers of mutant retina, consistent with a role for the pwi/WRB protein in TA-protein processing. The WRB protein was located near the apical domain and the ribbons in hair cells, and in the inner segment and the axon of the photoreceptor, consistent with a role in vesicle biogenesis or trafficking. Together, our results suggest that WRB plays a critical role in synaptic functions in these two sensory cells, and that disrupted processing of synaptic vesicle TA proteins explains much of the mutant phenotype. This article is protected by copyright. All rights reserved.
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