Purchase this article with an account.
Jeanne M. Frederick, Nataliia V. Krasnoperova, Kirstin Hoffmann, Jill Church–Kopish, Klaus Rüther, Kimberly Howes, Janis Lem, Wolfgang Baehr; Mutant Rhodopsin Transgene Expression on a Null Background. Invest. Ophthalmol. Vis. Sci. 2001;42(3):826-833.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
purpose. To study mechanisms leading to photoreceptor degeneration in mouse models
for autosomal dominant retinitis pigmentosa (adRP) based on the
rhodopsin P23H mutation.
methods. Mice of a transgenic line expressing a rhodopsin triple mutant,
V20G, P23H, and P27L (GHL), were mated with rhodopsin
(rho) knockout mice. Littermates of various ages
and genotypes (GHL+ rho +/+,
GHL+ rho +/−, and
GHL+ rho − /−)
were examined for outer nuclear layer thickness and outer segment
formation (histology), fate of mutant rhodopsin (immunocytochemistry),
and photoreceptor function (electroretinogram; ERG).
results. Mice expressing GHL-rhodopsin in the absence of wild-type rhodopsin had
severe retinopathy, which was nearly complete by postnatal day (P)30.
GHL-rhodopsin formed homodimers nearly exclusively on sodium dodecyl
sulfate–polyacrylamide gel electrophoresis gels, whereas wild-type
rhodopsin predominantly formed monomers. Expression level of mutant
rhodopsin in predegenerate (P10)
GHL+ rho − /− retinas
was low, approximately 10% to 25% of normal levels. No elaboration of
disc membrane or outer segment formation was observed at any time point
examined. The mutant rhodopsin was found mostly in perinuclear locales
(endoplasmic reticulum; ER) as evidenced by colocalization using the
antibodies Rho1D4 and calnexin-NT.
conclusions. GHL-rhodopsin dimerizes, localizes to the ER, and fails to transport
and support outer segment formation. Additionally, the mutant protein
does not support a scotopic ERG a-wave and accelerates photoreceptor
degeneration over that occurring with the rhodopsin knockout alone.
These findings indicate a cytotoxic effect of the mutant protein,
probably elicited by an unfolded protein
This PDF is available to Subscribers Only