Photoreceptors in whirler mice show defective transducin translocation and are susceptible to short-term light/dark changes-induced degeneration

Mei Tian, Weimin Wang, Duane Delimont, Linda Cheung, Marisa Zallocchi, Dominic Cosgrove, You Wei Peng

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Usher syndrome combines congenital hearing loss and retinitis pigmentosa (RP). Mutations in the whirlin gene (DFNB31/WHRN) cause a subtype of Usher syndrome (USH2D). Whirler mice have a defective whirlin gene. They have inner ear defects but usually do not develop retinal degeneration. Here we report that, in whirler mouse photoreceptors, the light-activated rod transducin translocation is delayed and its activation threshold is shifted to a higher level. Rhodopsin mis-localization is observed in rod inner segments. Continuous moderate light exposure can induce significant rod photoreceptor degeneration. Whirler mice reared under a 1500lux light/dark cycle also develop severe photoreceptor degeneration. Previously, we have reported that shaker1 mice, a USH1B model, show moderate light-induced photoreceptor degeneration with delayed transducin translocation. Here, we further show that, in both whirler and shaker1 mice, short-term moderate light/dark changes can induce rod degeneration as severe as that induced by continuous light exposure. The results from shaker1 and whirler mice suggest that defective transducin translocation may be functionally related to light-induced degeneration, and these two symptoms may be caused by defects in Usher protein function in rods. Furthermore, these results indicate that both Usher syndrome mouse models possess a light-induced retinal phenotype and may share a closely related pathobiological mechanism.

Original languageEnglish (US)
Pages (from-to)145-153
Number of pages9
JournalExperimental Eye Research
Volume118
DOIs
StatePublished - Jan 2014

Keywords

  • Light-induced degeneration
  • Photoreceptor degeneration
  • Retinitis pigmentosa
  • Shaker1
  • Transducin
  • Usher syndrome
  • Whirler

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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