Abstract
Purpose::
To report the phenotypic and genetic characterization of a new mouse mutant with a retinal degeneration, rd17, that is associated with the retinal function loss. rd17 is a new, naturally occurring mouse model of autosomal recessive retinal dysfunction and degeneration caused by the sequence alteration in the Gnat1 gene and a cpfl3 mutation in the Gnat2 gene.
Methods::
While screening mouse strains and stocks at The Jackson Laboratory for genetic mouse models of human ocular disorders, we discovered a new mouse retinal degeneration (allele symbol: rd17). The phenotype was documented using electroretinography, histology, and fundus photography, while genetic characterization and linkage analysis were performed using linkage analysis and gene identification methods.
Results::
Mice homozygous for rd17 show retinal function abnormalities at 3 weeks of age. Electroretinograms of rd17/rd17 mice are never normal. Histology at 2 months of age shows normal retina, but the fundus shows some signs of retinal degeneration (retinal white dots and attenuated vessels). The inheritance pattern of rd17 mutant alleles is autosomal recessive. Linkage analysis mapped this new mutation to mouse Chromosome 9, in Gnat1 region, and mouse Chromosome 3, in Gnat2 region. Sequence analysis showed that the dark-adapted ERG abnormality is caused by a sequence alteration in the Gnat1 gene and the light-adapted ERG abnormality is due to the cpfl3 mutation in the Gnat2 gene.
Conclusions::
The early onset of retinal function abnormalities combined with our genetic data suggest that this is a new digenic retinal disorder not previously described in mouse or human. Retinal degeneration 17 (rd17) may provide a novel mouse model for retinal transplantation studies because its retinal dysfunction would allow the detection of retinal function only from grafted cells.
Keywords: gene mapping • retinal degenerations: hereditary • genetics