title: 60 YEARS OF POMC: Transcriptional and epigenetic regulation of POMC gene expression.
abstract: Expression of the pro-opiomelanocortin (POMC) gene integrates numerous inputs that reflect the developmental history of POMC-expressing cells of the pituitary and hypothalamus, as well as their critical role in the endocrine system. These inputs are integrated at specific regulatory sequences within the promoter and pituitary or hypothalamic enhancers of the POMC locus. Investigations of developmental mechanisms and transcription factors (TFs) responsible for pituitary activation of POMC transcription led to the discovery of the Pitx factors that have critical roles in pituitary development and striking patterning functions in embryonic development. Terminal differentiation of the two pituitary POMC lineages, the corticotrophs and melanotrophs, is controlled by Tpit; mutations of the human TPIT gene cause isolated adrenocorticotrophic hormone deficiency. Intermediate lobe and melanotroph identity is provided by the pioneer TF Pax7 that remodels chromatin to reveal a new repertoire of enhancers for Tpit action. Many signaling pathways regulate POMC transcription including activation by hypothalamic corticotrophin-releasing hormone acting through the orphan nuclear receptors of the Nur family and feedback repression by glucocorticoids and their glucocorticoid receptor. TFs of the basic helix-loop-helix, Smad, Stat, Etv, and nuclear factor-B families also mediate signals for control of POMC transcription. Whereas most of these regulatory processes are conserved in different species, there are also notable differences between specific targets for regulation of the human compared with mouse POMC genes.
authors.affiliation: Laboratoire de génétique moléculaireInstitut de recherches cliniques de Montréal (IRCM), Montréal, Québec, Canada jacques.drouin@ircm.qc.ca.
authors.forename: Jacques
authors.initials: J
authors.lastname: Drouin
mesh_terms: D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D044127:Epigenesis, Genetic; D005786:Gene Expression Regulation / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D007031:Hypothalamus / Q000378:metabolism; D051761:Paired Box Transcription Factors / Q000378:metabolism; D047748:Pituitary ACTH Hypersecretion / Q000235:genetics / Q000378:metabolism; D010902:Pituitary Gland / Q000378:metabolism; D011333:Pro-Opiomelanocortin / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D050791:STAT Transcription Factors / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D000097577:Homeobox Protein PITX2
chemical_list: D003346:Corticotropin-Releasing Hormone; D016207:Cytokines; D005938:Glucocorticoids; D018398:Homeodomain Proteins; D051761:Paired Box Transcription Factors; D011333:Pro-Opiomelanocortin; D050791:STAT Transcription Factors; D014157:Transcription Factors; D000097577:Homeobox Protein PITX2; C101485:homeobox protein PITX1
keywords: ACTH; MSH; gene regulation; hypothalamus; pituitary; transcription