The orphan nuclear receptor estrogen-related receptor alpha is a transcriptional regulator of the human medium-chain acyl coenzyme A dehydrogenase gene.
Estrogen-related receptor alpha (ERR alpha) is an orphan member of the superfamily of nuclear hormone receptors. ERR alpha was initially isolated based on its sequence homology to the estrogen receptor but is not activated by classic estrogens. To identify possible physiologic functions for this orphan receptor, we cloned the mouse ERR alpha cDNA and used it to characterize the expression of ERR alpha transcripts and to identify potential ERR alpha target genes. RNA in situ hybridization studies detect ERR alpha transcripts in an organ-specific manner through mid- to late embryonic development, with persistent high-level expression in brown adipose tissue and intestinal mucosa. In the adult mouse, ERR alpha is most highly expressed in kidney, heart, and brown adipocytes, tissues which preferentially metabolize fatty acids. Binding site selection experiments show that ERR alpha preferentially binds to an ERR alpha response element (ERRE) containing a single consensus half-site, TNAAGGTCA. An ERRE is present in the 5'-flanking region of the gene encoding medium-chain acyl coenzyme A dehydrogenase (MCAD), a key enzyme involved in the mitochondrial beta-oxidation of fat. The MCAD nuclear receptor response element 1 (NRRE-1) interacts in vitro with ERR alpha expressed in COS-7 cells. Supershift experiments show that endogenous ERR alpha present in nuclear extracts obtained from a brown fat tumor cell line (HIB) interacts with NRRE-1. In the absence of its putative ligand, ERR alpha does not activate the MCAD promoter in transient transfection studies; however, a VP16-ERR alpha chimera activates natural and synthetic promoters containing NRRE-1. In addition, ERR alpha efficiently represses retinoic acid induction mediated by NRRE-1. These results demonstrate that ERR alpha can control the expression of MCAD through the NRRE-1 and thus may play an important role in regulating cellular energy balance in vivo.
Sladek
R
R
Molecular Oncology Group, Royal Victoria Hospital, Montréal, Québec, Canada.
Bader
J A
JA
Giguère
V
V
D042964:Acyl-CoA Dehydrogenase; D017667:Adipocytes / Q000166:cytology; D000818:Animals; D002454:Cell Differentiation; D003001:Cloning, Molecular; D044943:Fatty Acid Desaturases / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D005809:Genes, Regulator; D006367:HeLa Cells; D017405:Herpes Simplex Virus Protein Vmw65 / Q000235:genetics; D006801:Humans; D051379:Mice; D011401:Promoter Regions, Genetic; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D000097983:ERRalpha Estrogen-Related Receptor
D042964:Acyl-CoA Dehydrogenase; D044943:Fatty Acid Desaturases; D017405:Herpes Simplex Virus Protein Vmw65; D018160:Receptors, Cytoplasmic and Nuclear; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; D000097983:ERRalpha Estrogen-Related Receptor