COUP-TFI IS A POTENTIAL REGULATOR OF RETINOIC ACID-MODULATED DEVELOPMENT IN XENOPUS EMBRYOS

Isomers of retinoic acid are considered likely regulators of developme ntal pattern formation in vertebrate embryos. The orphan receptor COUP -TFI, which can alter cellular responses to retinoic acid in cultured cells, is expressed in distinct regions of the developing zebrafish an d mouse anterior central nervous system. We asked if COUP-TFI can modu late retinoic acid signaling and anterior neural development in a vert ebrate embryo by examining: (1) whether COUP-TFI could alter transcrip tional responses to retinoic acid in Xenopus embryonic explants, and ( 2) whether misexpression of COUP-TFI could regulate anterior neural ge ne expression during early Xenopus development. The results from these studies show that COUP-TFI is a potent regulator of retinoic acid-ind uced gene expression in Xenopus embryonic cells, and that misexpressio n of COUP-TFI causes deficiencies in anterior neural structures and he ad development in Xenopus embryos with a concomitant change in anterio r neural gene expression. These results support the proposition that C OUP-TFI has a role in the elaboration and patterning of anterior neura l gene expression in vertebrates, possibly via effects on the retinoic acid signaling pathways.