| First Author | Chang B | Year | 2024 |
| Journal | MGI Direct Data Submission | Mgi Jnum | J:348234 |
| Mgi Id | MGI:7640118 | Citation | Chang B (2024) The Crx |
| abstractText | The retinal degeneration 23 (rd23) heritable mutant phenotype was discovered in our ocular phenotypes screening program in April 2019 in strain B6;SJL-Tnfrsf14tm1.1Kro/J (JAX Stock No. 030862) that presented with retinal vessel attenuation and retinal degeneration at 5 weeks of age. We mated the mutant mice with C57BL/6J and all F1 mice had normal retinas. The retinal degeneration phenotype was recovered in the F2 generation and siblings were mated to homozygosity. rd23 is an autosomal recessive mutation and we have made a new congenic rd23 strain B6.Cg-rd23/BOC (JAX Stock No. 036967). Mice homozygous for the rd23 mutation show retinal degeneration with sclerotic retinal vessels at 4 weeks of age (Figure 1A) and OCT revealed progressive retinal outer nuclear layer (ONL) degeneration in rd23 mice (Figure 1A, 1B) comparing with wild type control (Figure 1C). By 4 months of age we found degeneration of the outer nuclear layer to the extent that only one layer of cells remained (Figure 1B and 1D). Electroretinograms of rd23/rd23 mice are never normal and are nondetectable compared with rd23/+ mice at 4 weeks of age (Figure 1). Genetic analysis showed that rd23 is caused by an autosomal recessive mutation that maps to mouse Chromosome 7 between D7Mit340 and D7Mit57, where the mouse cone-rod homeobox (Crx) gene is located. Sequence analysis revealed that the rd23 mutation is caused by a base pair change from G to C in the splicing zone of exon 2 of the Crx gene. cDNA analysis confirmed that this mutation results in the loss of exon 2 (Figure 2). Due to the loss of exon2, a frame shift leads to a stop codon at amino acid 202. This spontaneous Crx mutation provides a new mouse model for human Leber congenital amaurosis 7 and human cone-rod dystrophy 2. |
