Abstract
Purpose :
In humans with albinism, gene mutations impact melanin synthesis or melanosome biogenesis and trafficking in the retinal pigmented epithelium (RPE) and result in in the loss or abnormal development of the fovea, a pit-like depression in the back of the retina important for vison. As rodents and many other mammals such as dogs and cats lack a foveated retina, the link between the pigmentation pathway and fovea formation is poorly understood but almost certainly involves signaling between the RPE and non-pigmented neural retina. To explore this, we have developed a novel model system, Anolis sagrei or the brown anole, to study the cellular and molecular mechanisms underlying foveal development.
Methods :
By injecting CRISPR-Cas into the unfertilized oocytes of adult female A. sagrei lizards, we were able to create albino offspring. The hatchling eyes were sectioned and an H&E performed to provide morphological data about eye pigmentation and fovea formation.
Results :
We created oca2 -/- and tyr -/- mutant lizards. These displayed the characteristic lack of pigmentation in the skin and eyes associated with albinism. They also showed fovea hypoplasia in the temporal fovea and a loss of pigmentation in the choroid and/or RPE.
Conclusions :
We show here lizards harboring loss-of-function tyr and oca2 mutations exhibit an absence of pigmentation in the eye and fail to develop a temporal fovea, providing a foveated model system to continue studying albinism.
This is a 2020 ARVO Annual Meeting abstract.