Evidence of a tissue-restricting DNA regulatory element in the mouse IRBP promoter

The expression of interphotoreceptor retinoid binding protein (IRBP) is lim ited to photoreceptor cells of the retina and pinealocytes of the pineal gl and. We sought to define cis-elements of the mouse IRBP 5' flanking region that are required for this restricted activity. In vitro transient transfec tions of retinoblastoma and neuroblastoma cells and in vivo experiments wit h transgenic Xenopus laevis indicate that -1783/+101 and -156/+101 IRBP gen e fragments directed expression predominantly to the retina and pineal, wit h minor neuronal expression elsewhere. In contrast, a -701+101 fragment was less restrictive in controlling expression, exhibiting activity not only i n retina, but also in forebrain, hindbrain, spinal cord, and motor neurons innervating gills. (C) 2001 Federation of European Biochemical Societies. P ublished by Elsevier Science BY. All rights reserved.