Identification of the promoter region required for human adiponectin gene transcription: Association with CCAAT/enhancer binding protein-beta and tumor necrosis factor-alpha.
Adiponectin, an adipose tissue-specific plasma protein, is involved in insulin sensitizing and has anti-atherosclerotic properties. Plasma levels of adiponectin are decreased in obese individuals and patients with type 2 diabetes with insulin resistance. Tumor necrosis factor-alpha (TNF-alpha) decreases the expression of adiponectin in adipocytes. The aims of the present study were: (1) to identify the promoter region responsible for basal transcription of the human adiponectin gene, and (2) to investigate the mechanism by which adiponectin was regulated by TNF-alpha. The human adiponectin promoter (2.1kb) was isolated and used for luciferase reporter analysis by transient transfection into 3T3-L1 adipocytes. Deletion analysis demonstrated that the promoter region from -676 to +41 was sufficient for basal transcriptional activity. Mutation analysis of putative response elements for sterol regulatory element binding protein (SREBP) (-431 to -423) and CCAAT/enhancer binding protein (C/EBP) (-230 to -224) showed that both elements were required for basal promoter activity. Adiponectin transcription was increased 3-fold in cells that over-expressed constitutively active C/EBP-beta. Electrophoretic mobility shift assay, using nuclear extract from 3T3-L1 cells and the -258 to -199 region as a probe, demonstrated specific DNA-protein binding, which was abolished by TNF-alpha treatment. The present data indicate that the putative response elements for SREBP and C/EBP are required for human adiponectin promoter activity, and that suppression by TNF-alpha may, at least in part, be associated with inactivation of C/EBP-beta.
Kita
Atsushi
A
Unit of Metabolism/Diabetes and Clinical Nutrition, Nagasaki University, Japan.
Yamasaki
Hironori
H
Kuwahara
Hironaga
H
Moriuchi
Akie
A
Fukushima
Keiko
K
Kobayashi
Masakazu
M
Fukushima
Tetsuya
T
Takahashi
Ryoko
R
Abiru
Norio
N
Uotani
Shigeo
S
Kawasaki
Eiji
E
Eguchi
Katsumi
K
D041721:3T3-L1 Cells; D052242:Adiponectin; D000818:Animals; D001483:Base Sequence; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism*; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics*; D051379:Mice; D011401:Promoter Regions, Genetic / Q000235:genetics*; D020218:Response Elements / Q000235:genetics; D017384:Sequence Deletion / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects* / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D052242:Adiponectin; D022782:CCAAT-Enhancer-Binding Protein-beta; D036341:Intercellular Signaling Peptides and Proteins; D014409:Tumor Necrosis Factor-alpha