Steroid and nuclear receptors. Villefranche-sur-Mer, France, May 25-27, 1999.

Ever since the discovery of puff induction by ecdysone, gene regulation by steroid hormones has occupied a position at the frontier of progress in eukaryotic gene expression. Cloning of the hormone receptors revealed that they belong to a large family of nuclear receptors, including those for vitamin D3, thyroid hormones and retinoids. Because of their inducible nature, these receptors are now among the best characterized transcription factors in eukaryotes. Knowledge of the structure and the molecular mechanism of regulation by nuclear receptors of various cellular processes is progressing very rapidly. All nuclear receptors share a short DNA-binding region encompassing two zinc fingers and a hydrophobic ligandbinding domain, the three-dimensional structures of which have been elucidated. In the last decade, however, the number of nuclear receptors identified has expanded rapidly by the homology cloning of family members, many of which are so-called orphan receptors. These ‘receptors in search of a ligand’ have attracted considerable interest since they could help to uncover new endocrine regulatory systems. At the end of May, a group of some 200 scientists met in an old fortress at Villefranche-surMer near Nice to discuss novel findings on the structure and function of this large family of transcriptional regulators. The meeting lasted for three full days and covered a vast range of topics, from chromatin and transcription to gene targeting and development, including many aspects of cross-signalling, as well as the identification of new metabolic and endocrine regulatory pathways. In this report, we will summarize recent findings reported in the different areas with the intention of conveying a feeling for the present state of this rapidly evolving field. Owing to space limitations, we have had to select only a few of the many exciting data presented at the meeting. We apologize to those colleagues whose results are not discussed appropriately, in particular to those who described the advance in understanding the three-dimensional structure of the receptors and their interaction with other factors. This structural work has