title: Two populations of glucocorticoid receptor-binding sites in the male rat hippocampal genome.
abstract: In the present study, genomic binding sites of glucocorticoid receptors (GR) were identified in vivo in the rat hippocampus applying chromatin immunoprecipitation followed by next-generation sequencing. We identified 2470 significant GR-binding sites (GBS) and were able to confirm GR binding to a random selection of these GBS covering a wide range of P values. Analysis of the genomic distribution of the significant GBS revealed a high prevalence of intragenic GBS. Gene ontology clusters involved in neuronal plasticity and other essential neuronal processes were overrepresented among the genes harboring a GBS or located in the vicinity of a GBS. Male adrenalectomized rats were challenged with increasing doses of the GR agonist corticosterone (CORT) ranging from 3 to 3000 μg/kg, resulting in clear differences in the GR-binding profile to individual GBS. Two groups of GBS could be distinguished: a low-CORT group that displayed GR binding across the full range of CORT concentrations, and a second high-CORT group that displayed significant GR binding only after administering the highest concentration of CORT. All validated GBS, in both the low-CORT and high-CORT groups, displayed mineralocorticoid receptor binding, which remained relatively constant from 30 μg/kg CORT upward. Motif analysis revealed that almost all GBS contained a glucocorticoid response element resembling the consensus motif in literature. In addition, motifs corresponding with new potential GR-interacting proteins were identified, such as zinc finger and BTB domain containing 3 (Zbtb3) and CUP (CG11181 gene product from transcript CG11181-RB), which may be involved in GR-dependent transactivation and transrepression, respectively. In conclusion, our results highlight the existence of 2 populations of GBS in the rat hippocampal genome.
authors.affiliation: Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, 2300 RC Leiden, The Netherlands.
authors.forename: J Annelies E
authors.initials: JA
authors.lastname: Polman
authors.forename: E Ronald
authors.initials: ER
authors.lastname: de Kloet
authors.forename: Nicole A
authors.initials: NA
authors.lastname: Datson
mesh_terms: D000315:Adrenalectomy; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D047369:Chromatin Immunoprecipitation; D002874:Chromosome Mapping / Q000379:methods; D016678:Genome / Q000235:genetics*; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D054928:Validation Studies as Topic
chemical_list: D009419:Nerve Tissue Proteins; D011965:Receptors, Glucocorticoid