Super-resolution Microscopy Reveals Photoreceptor-Specific Subciliary Location and Function of Ciliopathy-Associated Protein CEP290

Authors

Valencia L Potter
Abigail R Moye
Michael A Robichaux
Theodore G Wensel

Publication Date

10-22-2021

Journal

JCI Insight

DOI

10.1172/jci.insight.145256

PMID

34520396

PMCID

PMC8564900

PubMedCentral® Posted Date

10-22-2021

PubMedCentral® Full Text Version

Post-print

Published Open-Access

yes

Keywords

Animals, Antigens, Neoplasm, Cell Cycle Proteins, Cilia, Ciliopathies, Cytoskeletal Proteins, Disease Models, Animal, Humans, Mice, Microscopy, Cell Biology, Ophthalmology, Genetic diseases, Mouse models, Retinopathy

Abstract

Mutations in the cilium-associated protein CEP290 cause retinal degeneration as part of multiorgan ciliopathies or as retina-specific diseases. The precise location and the functional roles of CEP290 within cilia and, specifically, the connecting cilia (CC) of photoreceptors, remain unclear. We used super-resolution fluorescence microscopy and electron microscopy to localize CEP290 in the CC and in the primary cilia of cultured cells with subdiffraction resolution and to determine effects of CEP290 deficiency in 3 mutant models. Radially, CEP290 localizes in close proximity to the microtubule doublets in the region between the doublets and the ciliary membrane. Longitudinally, it is distributed throughout the length of the CC whereas it is confined to the very base of primary cilia in human retinal pigment epithelium-1 cells. We found Y-shaped links, ciliary substructures between microtubules and membrane, throughout the length of the CC. Severe CEP290 deficiencies in mouse models did not prevent assembly of cilia or cause obvious mislocalization of ciliary components in early stages of degeneration. There were fewer cilia and no normal outer segments in the mutants, but the Y-shaped links were clearly present. These results point to photoreceptor-specific functions of CEP290 essential for CC maturation and stability following the earliest stages of ciliogenesis.

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