Retinoid-mediated Regulation of NR6A1, Prickle1 and Ror2 During Development of the Mouse Embryo

Abstract

Vitamin A and its derivatives, collectively termed retinoids, are essential for proper growth and development as well as maintenance of homeostasis in the adult. Retinoic acid (RA), the major biologically active vitamin A metabolite, is well characterized for its crucial roles in gene activation during embryogenesis. Our lab had previously performed a microarray analysis to identify genes induced by exogenous RA in the tailbud of early mouse embryos. Three genes were chosen from the microarray results for further investigation; Germ Cell Nuclear Factor (GCNF/NR6A1), Prickle1 (Pk1) and Ror2, the latter of which are known members of the planar cell polarity (PCP) pathway. These genes were further examined for RA regulation by embryo culture and RT-PCR, which strongly supported a direct regulatory mechanism of NR6A1 by RA. Further analysis aiming to identify a functional response element in the promoter of the targets was attempted, including chromatin immunoprecipitation (ChIP), made possible by the generation and characterization of a highly specific antibody against RARγ. This antibody was used in a ChIP promoter walk, which identified regions on target gene promoters that are occupied by RARγ in vivo, and therefore likely harbor RA response elements.