COOPERATIVITY IN TRANSACTIVATION BETWEEN RETINOIC ACID RECEPTOR AND TFIID REQUIRES AN ACTIVITY ANALOGOUS TO E1A

In embryonal carcinoma (EC) cells retinoic acid (RA) strongly induces transcription from the RA receptor beta-2 (RAR-beta-2) promoter through an RA response element (RARE) located in close proximity to the TATA box. Here we demonstrate that recombinant human TATA box-binding protein, hTFIID, and RAR functionally cooperate in transactivation of the RAR-beta-2 promoter in EC cells in a strictly RA-dependent manner. We demonstrate that the core domain of hTFIID is sufficient to mediate RAR-dependent transcription and that Drosophila, but not yeast, TFIID can substitute for hTFIID. In COS cells ectopic expression of the E1A protein is a prerequisite for hTFIID and RAR to cooperate in transactivation. We propose a model for transcriptional regulation of the RAR-beta-2 promoter in EC cells in which RAR, following activation by RA, functionally interacts with hTFIID via an E1A-like activity present in EC cells.