A PUTATIVE G-PROTEIN-COUPLED RECEPTOR, H218, IS DOWN-REGULATED DURINGTHE RETINOIC ACID-INDUCED DIFFERENTIATION OF F9 EMBRYONAL CARCINOMA-CELLS

We have previously cloned a novel guanine nucleotide-binding protein ( G-protein)-coupled receptor, H218, that has sequence similarity to a l ysophosphatidic acid receptor, edg2. We present here Northern analysis indicating that the H218 mRNA is expressed in undifferentiated F9 emb ryonal carcinoma cells. The H218 message is down-regulated and its sta bility is decreased during retinoic acid-and dibutyryl cAMP-induced di fferentiation. Treatment by various receptor-selective retinoids indic ated that retinoic acid receptor beta or gamma signaling, but not reti noid X receptor activation, is required for the down-regulation of H21 8 mRNA. Activation of the H218 receptor may contribute to the phenotyp e of undifferentiated F9 embryonal carcinoma cells. (C) 1998 Academic Press.