title: Nuclear Factor-Y is an adipogenic factor that regulates leptin gene expression.
abstract: OBJECTIVE
  Leptin gene expression is highly correlated with cellular lipid content in adipocytes but the transcriptional mechanisms controlling leptin expression in vivo are poorly understood. In this report, we set out to identify cis- and trans-regulatory elements controlling leptin expression.
  
  
  METHODS
  Leptin-BAC luciferase transgenic mice combining with other computational and molecular techniques were used to identify transcription regulatory elements including a CCAAT-binding protein Nuclear Factor Y (NF-Y). The function of NF-Y in adipocyte was studied in vitro with 3T3-L1 cells and in vivo with adipocyte-specific knockout of NF-Y.
  
  
  RESULTS
  Using Leptin-BAC luciferase mice, we showed that DNA sequences between -22 kb and +8.8 kb can confer quantitative expression of a leptin reporter. Computational analysis of sequences and gel shift assays identified a 32 bp sequence (chr6: 28993820-2899385) consisting a CCAAT binding site for Nuclear Factor Y (NF-Y) and this was confirmed by a ChIP assay in vivo. A deletion of this 32 bp sequence in the -22 kb to +8.8 kb leptin-luciferase BAC reporter completely abrogates luciferase reporter activity in vivo. RNAi mediated knockdown of NF-Y interfered with adipogenesis in vitro and adipocyte-specific knockout of NF-Y in mice reduced expression of leptin and other fat specific genes in vivo. Further analyses of the fat specific NF-Y knockout revealed that these animals develop a moderately severe lipodystrophy that is remediable with leptin therapy.
  
  
  CONCLUSIONS
  These studies advance our understanding of leptin gene expression and show that NF-Y controls the expression of leptin and other adipocyte genes and identifies a new form of lipodystrophy.
authors.affiliation: Laboratory of Molecular Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
authors.forename: Yi-Hsueh
authors.initials: YH
authors.lastname: Lu
authors.affiliation: Laboratory of Molecular Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
authors.forename: Olof Stefan
authors.initials: OS
authors.lastname: Dallner
authors.affiliation: Laboratory of Molecular Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
authors.forename: Kivanc
authors.initials: K
authors.lastname: Birsoy
authors.affiliation: Laboratory of Molecular Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
authors.forename: Gulya
authors.initials: G
authors.lastname: Fayzikhodjaeva
authors.affiliation: Laboratory of Molecular Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA ; Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Friedman
keywords: Adipocyte; Adipogenesis; Leptin; NF-Y; Transcriptional regulation