INDUCTION OF HOX-2 GENES IN P19 EMBRYOCARCINOMA CELLS IS DEPENDENT ON RETINOIC ACID RECEPTOR-ALPHA

Abstract In vertebrate embryos retinoic acid can act as a teratogen and may have a natural function as a morphogen. In both cases the mechanism by which retinoic acid exerts its effect may involve alteration of the level of HOX gene transcription. We have investigated the role of retinoic acid receptor α (RARα) in retinoic acid-dependent induction of HOX-2 gene expression in embryocarcinoma (EC) cells by using the P19 RAC65 EC cell line, which is retinoic acid-resistant due to the expression of a dominant negative RARα. No induction of HOX-2 genes by retinoic acid was seen, while in P19 RAC65 EC cells stably transfected with human RARα under the control of a constitutive promoter HOX-2 gene induction is restored. This shows that RARα is involved in HOX gene induction by retinoic acid.