The palindromic DNA-bound USP/EcR nuclear receptor adopts an asymmetric organization with allosteric domain positioning.
Fiche publication
Date publication
janvier 2014
Auteurs
Membres identifiés du Cancéropôle Est :
Dr MORAS Dino, Dr KLAHOLZ Bruno, Dr BILLAS Isabelle
Tous les auteurs :
Maletta M, Orlov I, Roblin P, Beck Y, Moras D, Billas IM, Klaholz BP
Lien Pubmed
Résumé
Nuclear receptors (NRs) regulate gene expression through DNA- and ligand-binding and thus represent crucial therapeutic targets. The ultraspiracle protein/ecdysone receptor (USP/EcR) complex binds to half-sites with a one base pair spaced inverted repeat (IR1), a palindromic DNA response element (RE) reminiscent of IRs observed for vertebrate steroid hormone receptors. Here we present the cryo electron microscopy structure of the USP/EcR complex bound to an IR1 RE which provides the first description of a full IR-bound NR complex. The structure reveals that even though the DNA is almost symmetric, the complex adopts a highly asymmetric architecture in which the ligand-binding domains (LBDs) are positioned 5' off-centred. Additional interactions of the USP LBD with the 5'-flanking sequence trigger transcription activity as monitored by transfection assays. The comparison with DR-bound NR complexes suggests that DNA is the major allosteric driver in inversely positioning the LBDs, which serve as the main binding-site for transcriptional regulators.
Référence
Nat Commun. 2014 Jun 19;5:4139