Multipotential stem cells and progenitors in the vertebrate retina

cells can also be derived from two or perhaps threeABSTRACT: The vertebrate retina is derived additional sources after retinal damage: (a) the reti-from paired evaginations from the neural tube in em-nal pigmented epithelium (RPE) in amphibians andbryonic development and is initially produced by pro-embryonic chicks and mammals; (b) a specialized rodgenitor cells similar to those that generate the neurons progenitor in fish; and (c) the Müller glial cells. Whileand glia of other areas of the central nervous system. there is currently no evidence for a neural/glial stemIn some amphibians and fish, the retina continues to cell in the adult mammalian retina, and the retinagrow along with the eye throughout the life of the of the mature mammal does not show regenerativeanimal. The new retinal cells are added at the ciliary capacity after damage, there is a possibility for themargin of the eye from the mitotic activity of neural/ reinitiation of stem cell potential at the peripheralglial stem cells in a region known as the germinal retinal margin, from the RPE or from the Müller glialzone and are seamlessly incorporated into the existing cells. The application of information derived from theretinal circuitry. Little is known about the cell or mo-studies of retinal progenitor cells in developing organ-lecular biology of these stem cells; however, studies isms should soon provide a test of these possibilities.of retinal progenitor cells in chick and mammalian q 1998 John Wiley & Sons, Inc. J Neurobiol 36: 206–220, 1998embryos have led to the identification of several fac