The nuclear receptor transcription factor, retinoid-related orphan receptor β, regulates retinal progenitor proliferation

We examined the role of retinoid-related orphan receptor (ROR)beta, a member of the nuclear receptor family of transcription factors, in retinal neurogenesis. In situ hybridization studies showed that ROR beta is expressed in retinal progenitor cells in the embryonic rat retina. Further studies demonstrated that ROR beta colocalizes with Chx10, a transcription factor thought to influence retinal progenitor proliferation (Burmeister, M., Novak, J., Liang, M-Y., Basu, S., Ploder, L., Hawes, N.L. Vidgen, D., Hoover, F., Goldman, D., Kalnins, V.L, Roderick, T.H., Taylor, B.A., Hankin, M.H. and McInnes, R.R., 1996. Ocular retardation mouse caused by Chx10 homeobox null allele: impaired retinal progenitor proliferation and bipolar cell differentiation. Nat. Genet. 12, 376-383). Northern analysis reveals that ROR beta expression is dramatically decreased in the ocular retardation(J) mutant, which possesses a defect in the Chx10 gene. Overexpression of ROR beta in retinal progenitors by biolistic transfection results in an increase in the number of large cell clones. These data support a role for ROR beta in regulating retinal progenitor proliferation, possibly via the Chx10 gene. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.