Persistent Progenitors at the Retinal Margin ofptc+/- Mice

Open Access
Publisher Website
Google Scholar
Abstract
The hedgehog signaling pathway is a key regulator of neural development, affecting both proliferation and differentiation of neural progenitors. Sonic hedgehog (Shh) is a mitogenic factor for retinal progenitorsin vitro. To determine whether this signaling system is importantin vivofor regulating retinal progenitor proliferation, we analyzed mice with a single functional allele of the Shh receptorpatched(ptc). We found thatptc+/- mice had increased numbers of neural progenitors at every stage of retinal development that we examined. In addition, these mice had persistent progenitors at the retinal margin for up to 3 months of age, reminiscent of the ciliary marginal zone of lower vertebrates. To test whether the progenitors at the retinal margin ofptc+/- mice could be induced to regenerate retinal neurons in response to damage, we bredptc+/- mice onto a retinal degeneration background (pro23his rhodopsin transgenic) and labeled newly generated cells with combined immunohistochemistry for bromodeoxyuridine and retinal neuron and photoreceptor-specific markers. We found newly generated neurons and photoreceptors at the retinal margin inptc+/-;pro23his mice. We propose that the Shh pathway may act as a regulator of both prenatal and postnatal retinal growth.