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The ciliopathy gene cc2d2a controls zebrafish photoreceptor outer segment development through a role in Rab8-dependent vesicle trafficking. Hum Mol Genet 2011 Oct 15;20(20):4041-55



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Pubmed Central ID




Scopus ID

2-s2.0-80053166268   73 Citations


Ciliopathies are a genetically and phenotypically heterogeneous group of human developmental disorders whose root cause is the absence or dysfunction of primary cilia. Joubert syndrome is characterized by a distinctive hindbrain malformation variably associated with retinal dystrophy and cystic kidney disease. Mutations in CC2D2A are found in ∼10% of patients with Joubert syndrome. Here we describe the retinal phenotype of cc2d2a mutant zebrafish consisting of disorganized rod and cone photoreceptor outer segments resulting in abnormal visual function as measured by electroretinogram. Our analysis reveals trafficking defects in mutant photoreceptors affecting transmembrane outer segment proteins (opsins) and striking accumulation of vesicles, suggesting a role for Cc2d2a in vesicle trafficking and fusion. This is further supported by mislocalization of Rab8, a key regulator of opsin carrier vesicle trafficking, in cc2d2a mutant photoreceptors and by enhancement of the cc2d2a retinal and kidney phenotypes with partial knockdown of rab8. We demonstrate that Cc2d2a localizes to the connecting cilium in photoreceptors and to the transition zone in other ciliated cell types and that cilia are present in these cells in cc2d2a mutants, arguing against a primary function for Cc2d2a in ciliogenesis. Our data support a model where Cc2d2a, localized at the photoreceptor connecting cilium/transition zone, facilitates protein transport through a role in Rab8-dependent vesicle trafficking and fusion.

Author List

Bachmann-Gagescu R, Phelps IG, Stearns G, Link BA, Brockerhoff SE, Moens CB, Doherty D


Brian A. Link PhD Professor in the Cell Biology, Neurobiology and Anatomy department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals, Genetically Modified
Gene Knockout Techniques
HEK293 Cells
Membrane Proteins
Protein Binding
Protein Transport
Retinal Photoreceptor Cell Outer Segment
Transport Vesicles
Vesicular Transport Proteins
Vision, Ocular
Zebrafish Proteins
rab GTP-Binding Proteins
jenkins-FCD Prod-486 e3098984f26de787f5ecab75090d0a28e7f4f7c0