Retinoids and their receptors in differentiation, embryogenesis, and neoplasia.

TLDR: The similarity of the mode of action of retinoids to that of the steroid and thyroid hormones has recently been demonstrated with the discovery of the nuclear receptors for retinoic acid, which belong to the steroid/thyroid hormone receptor superfamily.

Abstract: The crucial role of retinoids in controlling differentiation processes has become evident from studies conducted in a variety of in vivo and in vitro systems. Most striking is the role of retinoic acid as a morphogenic substance in vertebrate limb development, but equally important is its role in the maintenance of epithelial integrity in most superficial linings of the body. The similarity of the mode of action of retinoids to that of the steroid and thyroid hormones has recently been demonstrated with the discovery of the nuclear receptors for retinoic acid, which belong to the steroid/thyroid hormone receptor superfamily. These receptors act as transcriptional activators by binding as heterodimers to specific nucleotide sequences in the response elements of target genes. Response elements for retinoic acid have so far been identified for the rat growth hormone and phosphoenolpyruvate carboxykinase, the mouse complement H and laminin B1, the human and mouse retinoic acid receptor beta, the human osteoca...