This semidominant X-linked mutation causes a blond appearance to the fundus in homozygous females and hemizygous males, while heterozygous females develop diffuse white spots covering the retina beginning at 6 weeks of age.Read More +
This semidominant X-linked mutation causes a blond appearance to the fundus in homozygous females and hemizygous males, while heterozygous females develop diffuse white spots covering the retina beginning at 6 weeks of age.
The mutation retinal degeneration 9 arose spontaneously on C57BL/6J in approximately 1998 at The Jackson Laboratory. It has been maintained on the C57BL/6J background ever since.
|Allele Name||retinal degeneration 9|
|Allele Type||Spontaneous (Modified isoform(s))|
|Gene Symbol and Name||Rpgr, retinitis pigmentosa GTPase regulator|
|Strain of Origin||C57BL/6J|
|General Note||Rd9 is an X-linked semidominant retinal degeneration model. In Rd9 mutants, the retina is covered with diffuse white spots (mottled). The fundus appears normal at weaning age and the retina becomes mottled starting at 6 weeks of age in heterozygous females. The fundus of homozygous females and hemizygous males have a blond appearance. Retinal pigment loss and electroretinogram response decreases with age (J:75095).|
|Molecular Note||Sequence analysis identified a 32-bp duplication in the alternatively-spliced exon ORF15. The duplication produces a frame shift in the repetitive region of ORF15 that introduces a premature-stop codon, and is predicted to result in a truncated protein in which the C-terminal 108 amino acids are unrelated to the wild-type protein and are predominantly basic. RT-PCR confirmed expression of both the constitutive variant encoding exons 1-19 and the isoform encoding exons 1-13 and ORF15. However, the ORF15 isoform protein is not detected in immunoblot of retinal extracts or connecting cilia, while wild-type levels of the constitutive isoform Rpgr 1-19 are present in retinal lysates and are decreased in photoreceptor cells.|