Age-related retinal degeneration (arrd2) in a novel mouse model due to a nonsense mutation in the Mdm1 gene.

Kleins Lab // Publications // Dec 15 2008

PubMed ID: 18805803

Author(s): Chang B, Mandal MN, Chavali VR, Hawes NL, Khan NW, Hurd RE, Smith RS, Davisson ML, Kopplin L, Klein BE, Klein R, Iyengar SK, Heckenlively JR, Ayyagari R. age-related retinal degeneration (arrd2) in a novel mouse model due to a nonsense mutation in the Mdm1 gene. Hum Mol Genet. 2008 Dec 15;17(24):3929-41. doi: 10.1093/hmg/ddn295. Epub 2008 Sep 18. PMID 18805803

Journal: Human Molecular Genetics, Volume 17, Issue 24, Dec 2008

We observed that a naturally occurring mouse strain developed age-related retinal degeneration (arrd2). These mice had normal fundi, electroretinograms (ERGs) and retinal histology at 6 months of age; vessel attenuation, RPE atrophy and pigmentary abnormalities at 14 months, which progressed to complete loss of photoreceptors and extinguished ERG by 22 months. Genetic analysis revealed that the retinal degeneration in arrd2 segregates in an autosomal recessive manner and the disease gene localizes to mouse chromosome 10. A positional candidate cloning approach detected a nonsense mutation in the mouse double minute-1 gene (Mdm1), which results in the truncation of the putative protein from 718 amino acids to 398. We have identified a novel transcript of the Mdm1 gene, which is the predominant transcript in the retina. The Mdm1 transcript is localized to the nuclear layers of neural retina. Expression of Mdm1 in the retina increases steadily from post-natal day 30 to 1 year, and a high level of Mdm1 are subsequently maintained. The Mdm1 transcript was found to be significantly depleted in the retina of arrd2 mice and the transcript was observed to degrade by nonsense-mediated decay. These results indicate that the depletion of the Mdm1 transcript may underlie the mechanism leading to late-onset progressive retinal degeneration in arrd2 mice. Analysis of a cohort of patients with age-related macular degeneration (AMD) wherein the susceptibility locus maps to chromosome 12q, a region bearing the human ortholog to MDM1, did not reveal association between human MDM1 and AMD.