Ift172 conditional knock-out mice exhibit rapid retinal degeneration and protein trafficking defects

Hum Mol Genet. 2018 Jun 1;27(11):2012-2024. doi: 10.1093/hmg/ddy109.

Abstract

Intraflagellar transport (IFT) is a bidirectional transport process that occurs along primary cilia and specialized sensory cilia, such as photoreceptor outersegments. Genes coding for various IFT components are associated with ciliopathies. Mutations in IFT172 lead to diseases ranging from isolated retinal degeneration to severe syndromic ciliopathies. In this study, we created a mouse model of IFT172-associated retinal degeneration to investigate the ocular disease mechanism. We found that depletion of IFT172 in rod photoreceptors leads to a rapid degeneration of the retina, with severely reduced electroretinography (ERG) responses by 1 month and complete outer-nuclear layer (ONL) degeneration by 2 months. We investigated molecular mechanisms of degeneration and show that IFT172 protein reduction leads to mislocalization of specific photoreceptor outersegment (OS) proteins (RHO, RP1, IFT139), aberrant light-driven translocation of alpha transducin and altered localization of glioma-associated oncogene family member 1 (GLI1). This mouse model exhibits key features of the retinal phenotype observed in patients with IFT172-associated blindness and can be used for in vivo testing of ciliopathy therapies.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Carrier Proteins / genetics*
  • Cilia / genetics*
  • Cilia / pathology
  • Cytoskeletal Proteins
  • Disease Models, Animal
  • Electroretinography
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics*
  • Mice
  • Mice, Knockout
  • Mutation
  • Retina / diagnostic imaging
  • Retina / pathology
  • Retinal Degeneration / diagnostic imaging
  • Retinal Degeneration / genetics*
  • Retinal Degeneration / pathology
  • Retinal Rod Photoreceptor Cells / pathology
  • Zinc Finger Protein GLI1 / genetics

Substances

  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • Cytoskeletal Proteins
  • Gli1 protein, mouse
  • IFT172 protein, human
  • Ift172 protein, mouse
  • Intracellular Signaling Peptides and Proteins
  • Zinc Finger Protein GLI1