DISCOVERING THE REGULATORY LOGIC OF AN ANCIENT, EVOLUTIONARILY CONSERVED NUCLEAR RECEPTOR ENHANCER MODULE

Abstract

Event Abstract Back to Event DISCOVERING THE REGULATORY LOGIC OF AN ANCIENT, EVOLUTIONARILY CONSERVED NUCLEAR RECEPTOR ENHANCER MODULE Pia Bagamasbad1, Ronald Bonett2 and Robert J. Denver1* 1 University of Michigan, Molecular, Cellular and Developmental Biology, United States 2 The University of Tulsa, Biological Science, United States Different hormones may cooperate to regulate physiology and development. A striking example is the acceleration of tadpole metamorphosis by the synergistic actions of thyroid hormone (T3) and glucocorticoid (GC). Krüppel-like factor 9 (KLF9) is a transcription factor that mediates hormone action during development; the Klf9 gene is directly regulated by T3 receptor (TR) and GC receptor (GR). We investigated whether the Klf9 gene is synergistically transactivated by T3 plus GC. Gene expression analysis in frog and mouse cell lines, and in tadpole brain showed that treatment with T3 plus GC synergistically transactivated Klf9. Kinetic analysis of mRNA and heteronuclear RNA accumulation supported that synergy occurred at the transcriptional level. Transfection assays with reporter constructs containing 1 kb fragments of the 5’ flanking region of the frog Klf9 gene identified a region between -5 and -6 kb that supported synergistic transactivation. Comparative sequence analysis showed an evolutionarily conserved region of ~180 bp within the -5 to -6 kb fragment. The frog and mouse ~180 bp sequences supported synergistic transactivation, supporting that this region comprises an enhancer module. In silico analysis identified several putative hormone response elements (HREs) for TR and GR. Using gel shift, DNAseI footprinting and chromatin immunoprecipitation (ChIP) assays we found that TR and GR associate with specific sequences within the enhancer module. Site-directed mutagenesis of any of the HRE half sites abolished the synergistic response, supporting that direct DNA binding by TR and GR are necessary for synergistic transactivation. ChIP assays spanning the Klf9 locus for acetylated histones 3 and 4 showed elevated histone acetylation at the NR synergy module, but no augmentation of acetylation by combined hormone treatment. We are now investigating differential recruitment of RNA polymerase II as a possible molecular basis for hormone synergy. Acknowledgements Supported by NIH grant R01 NS046690 and NSF grant IOS 0922583 to RJD Keywords: Chromatin, Glucorticoid, metamorphosis, nuclear receptor, Synergy, thyroid, transcription Conference: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology, Ann Arbor, United States, 13 Jul - 16 Jul, 2011. Presentation Type: Oral Presentation Topic: Nuclear receptors Citation: Bagamasbad P, Bonett R and Denver RJ (2011). DISCOVERING THE REGULATORY LOGIC OF AN ANCIENT, EVOLUTIONARILY CONSERVED NUCLEAR RECEPTOR ENHANCER MODULE. Front. Endocrinol. Conference Abstract: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology. doi: 10.3389/conf.fendo.2011.04.00002 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 18 Jul 2011; Published Online: 09 Aug 2011. * Correspondence: Prof. Robert J Denver, University of Michigan, Molecular, Cellular and Developmental Biology, Ann Arbor, United States, Rdenver@umich.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Pia Bagamasbad Ronald Bonett Robert J Denver Google Pia Bagamasbad Ronald Bonett Robert J Denver Google Scholar Pia Bagamasbad Ronald Bonett Robert J Denver PubMed Pia Bagamasbad Ronald Bonett Robert J Denver Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.