Brain-specific homeobox factor as a target selector for glucocorticoid receptor in energy balance

Mol Cell Biol. 2013 Jul;33(14):2650-8. doi: 10.1128/MCB.00094-13. Epub 2013 May 13.

Abstract

The molecular basis underlying the physiologically well-defined orexigenic function of glucocorticoid (Gc) is unclear. Brain-specific homeobox factor (Bsx) is a positive regulator of the orexigenic neuropeptide, agouti-related peptide (AgRP), in AgRP neurons of the hypothalamic arcuate nucleus. Here, we show that in response to fasting-elevated Gc levels, Gc receptor (GR) and Bsx synergize to direct activation of AgRP transcription. This synergy is dictated by unique sequence features in a novel Gc response element in AgRP (AgRP-GRE). In contrast to AgRP-GRE, Bsx suppresses transactivation directed by many conventional GREs, functioning as a gene context-dependent modulator of GR actions or a target selector for GR. Consistent with this finding, AgRP-GRE drives fasting-dependent activation of a target gene specifically in GR(+) Bsx(+) AgRP neurons. These results define AgRP as a common orexigenic target gene of GR and Bsx and provide an opportunity to identify their additional common targets, facilitating our understanding of the molecular basis underlying the orexigenic activity of Gc and Bsx.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agouti-Related Protein / genetics
  • Agouti-Related Protein / metabolism
  • Animals
  • Arcuate Nucleus of Hypothalamus / cytology
  • Arcuate Nucleus of Hypothalamus / metabolism
  • Base Sequence
  • Binding Sites
  • Cell Line
  • Conserved Sequence
  • Dexamethasone / pharmacology
  • Energy Metabolism*
  • Gene Expression
  • Gene Expression Regulation
  • Genes, Reporter
  • Glucocorticoids / pharmacology
  • Glucocorticoids / physiology
  • Green Fluorescent Proteins / biosynthesis
  • Green Fluorescent Proteins / genetics
  • Homeodomain Proteins / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Nerve Tissue Proteins / physiology*
  • Neurons / metabolism*
  • Neuropeptide Y / genetics
  • Neuropeptide Y / metabolism
  • Organ Specificity
  • Protein Binding
  • Receptors, Glucocorticoid / metabolism*
  • Response Elements
  • Signal Transduction

Substances

  • Agouti-Related Protein
  • Bsx protein, mouse
  • Glucocorticoids
  • Homeodomain Proteins
  • Nerve Tissue Proteins
  • Neuropeptide Y
  • Receptors, Glucocorticoid
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • Dexamethasone