ABSTRACT
Cyclin D1-deficient mice have small eyes with thin retinas. We observed that there was a lower level of retinal cell proliferation and a unique pattern of photoreceptor cell death. Death was first observed in scattered clusters of cells in the retina. It then appeared to spread from these few cells to nearby photoreceptors, eventually producing extensive holes in the photoreceptor layer. These holes appeared to be filled with interneurons from the inner nuclear layer. The death mainly occurred during the second to fourth postnatal weeks. Other models of photoreceptor degeneration in rodents differ in that they occur more uniformly across the retina, with death proceeding over a longer period of time until all, or nearly all, of the photoreceptors degenerate. We also tested whether expression of a bcl-2 transgene could prevent the death and found that it could not.
Subject(s)
Cyclin D1/genetics , Mutation , Photoreceptor Cells/abnormalities , Photoreceptor Cells/pathology , Animals , Apoptosis/genetics , Cell Count , Genes, bcl-2 , Immunohistochemistry , Interneurons/pathology , Mice , Mice, Inbred DBA , Mice, Knockout , Mice, Transgenic , Microscopy, Electron , Mitosis , Models, Biological , Nerve Degeneration/genetics , Photoreceptor Cells/metabolism , Retina/abnormalities , Retina/metabolism , Retina/pathology , Rod Cell Outer Segment/abnormalities , Rod Cell Outer Segment/metabolism , Rod Cell Outer Segment/pathologyABSTRACT
In 020/A mice, homozygous for the retinal degeneration slow (rds) gene, the photoreceptor cells fail to develop outer segments, and in the absorption spectra of retinal extracts the rhodopsin peak is lacking. Application of an enzyme-linked immunoassay using antisera against bovine opsin shows, however, that opsin is present in the homozygous mutant retina (0.010 nmol/eye) at 3% of the level of the normal retina (0.38 nmol/eye) of Balb/c mice. In the retina of heterozygous mice the opsin level (0.19 nmol/eye) is about half of the normal. Detection of opsin in the rds mutant retina demonstrates the functional basis for the reported electroretinographic response and light-mediated reduction in cyclic nucleotide levels in this mutant.
Subject(s)
Eye Proteins/metabolism , Photoreceptor Cells/abnormalities , Retinal Degeneration/metabolism , Rod Cell Outer Segment/abnormalities , Animals , Enzyme-Linked Immunosorbent Assay , Eye Proteins/genetics , Mice , Mice, Inbred BALB C , Mice, Mutant Strains , Retinal Degeneration/genetics , Rod OpsinsABSTRACT
A recessively inherited retinopathy in collies aged 8 to 189 days was studied by light and electron microscopy. The disease is produced when the outer segments of rods and cones fail to develop normally. Retinal pigment epithelial changes found in several litters appeared to form a separate disease entity. We compared the collie retinopathy with other canine models and the collie ectasia syndrome.
