The subcellular localization of OTX2 is cell-type specific and developmentally regulated in the mouse retina

Recent evidence implicates homeodomain-containing proteins in the specifica tion of cell fates in the central nervous system. Here we report that in th e embryonic mouse eye Otx2, a paired homeodomain transcription factor, was found in retinal pigment epithelial cells and a restricted subset of retina l neurons, including ganglion cells. In the postnatal and adult eye, howeve r, both the cellular and subcellular distribution of the Otx2 protein were cell type-specific. Otx2 was detected only in the nuclei of retinal pigment epithelial and bipolar cells, but was present in the cytoplasm of rod phot oreceptors. Immunohistochemical studies of retinal explants and transfected cell lines both suggested that the retention of Otx2 in the cytoplasm of i mmature rods is a developmentally regulated process. The differential distr ibution of Otx2 in the cytoplasm of rods and the nucleus of other cell type s, suggests that subcellular localization of this transcription factor may participate cell fate determination during specific phases of retinal devel opment. (C) 2000 Elsevier Science B.V. All rights reserved.