CEP290 is required for photoreceptor ciliogenesis and other cilia related functions

摘要

Mutations in CEP290, which encodes a centrosomal/cilia protein, result in a broad range of human ciliopathiesfrom isolated Leber congenital amaurosis to lethalMeckel-Gruber syndrome. By light microscopy, CEP290localizes to the ependymal cells lining the lateral ventricles,to respiratory airways, and to ciliated cells of thekidney. By immunoEM in photoreceptors, CEP290 localizesto ciliary microtubules of the connecting cilium. Wegenerated a null allele of Cep290 in mice by replacingexons 1-4 of the Cep290 gene with a lacZ-neo cassetteand analyzed Cep290-knockout mouse phenotypes.Cep290ko/ko mice develop hydrocephalus and most (80-100%, strain-dependent) die by one month. Both C57BL/6 and 129SvJ backgrounds reduce viability of Cep290ko/ko mice. High-resolution MRI of the brain demonstratesenlarged ventricles and other morphological abnormalities.By SEM ependymal cells in the Cep290ko/ko micehave reduced numbers of unorganized cilia, in contrastto the tufts of cilia lining the WT ventricular epithelium.Knockout mice having subclinical hydrocephalus surviveand reproduce normally. Photoreceptors fail to generateconnecting cilia or outer segments in Cep290ko/ko mice,although basal bodies and associated microtubule assembliesare found. The presence of basal bodies and microtubulerings without connecting cilia or outer segmentsindicates that CEP290 is essential for ciliogenesis inphotoreceptors. Most photoreceptors die between P14and P28. Cep290ko/+ mice do not have retinal degenerationor hydrocephalus, demonstrating haplosufficiency.Our results indicate that CEP290 plays a critical role inciliogenesis and cilia function in subsets of neurons andhave begun to shed light on underlying mechanisms inciliopathies.