EXPRESSION OF WINGED HELIX GENES, BF-1 AND BF-2, DEFINE ADJACENT DOMAINS WITHIN THE DEVELOPING FOREBRAIN AND RETINA

One of the earliest events in the development of the central nervous s ystem is the establishment of positional identity along the anteropost erior (A-P) axis of the neuroepithelium. In recent years, regulatory g enes with regionally restricted expression in the neuroepithelium have been identified which are believed to specify its developmental fate. We have previously described Brain Factor-1 (BF-1), a winged helix (W H) transcription factor expressed in the telencephalic neuroepithelium (Tao and Lai, 1992) Neuron 8:957-966. Here we report the cloning of t he mouse cDNA for a novel WH protein, BF-2. We show that BF-2 is a seq uence-specific DNA binding protein with a binding specificity distinct from BP-1. Its expression in the CNS during embryogenesis is restrict ed to the rostral diencephalic neuroepithelium. The caudal boundary of BF-2 expression is at the zona limitans intrathalamica. Rostrally, th e BF-2 expression domain is adjacent to that of BF-1. The expression d omains of these two factors define a boundary within the developing fo rebrain neuroepithelium. The BF-1/BP-2 boundary also extends laterally to divide the optic stalk and the retina into nasal(anterior) and tem poral(posterior) domains. These observations suggest that in addition to playing a role in the subdivision of the forebrain, these two WH fa ctors may also function to establish positional information in the ret inal neuroepithelium. (C) 1994 John Wiley and Sons, Inc.