Regulation of peroxisome proliferator-activated receptor gamma expression by adipocyte differentiation and determination factor 1/sterol regulatory element binding protein 1: implications for adipocyte differentiation and metabolism
Authors: M Briggs
J Auwerx
L Gelman
G Martin
B M Spiegelman
J B Kim
K Schoonjans
L Fajas
J C Fruchart
J Najib
Journal: Molecular and Cellular Biology (1999)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: PPARgamma; adipocyte differentiation; insulin sensitivity; ADD-1/SREBP-1; transcription factor
Affiliations: LBRE, U 325 INSERM, Institut Pasteur, F-59019 Lille, France., LBRE, U 325 INSERM, Institut Pasteur, F-59019 Lille, France
1
;, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115
2
; and, Ligand Pharmaceuticals, San Diego, California 921213

Abstract:  Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor implicated in adipocyte differentiation and insulin sensitivity. We investigated whether PPARgamma expression is dependent on the activity of adipocyte differentiation and determination factor 1/sterol regulatory element binding protein 1 (ADD-1/SREBP-1), another transcription factor associated with both adipocyte differentiation and cholesterol homeostasis. Ectopic expression of ADD-1/SREBP-1 in 3T3-L1 and HepG2 cells induced endogenous PPARgamma mRNA levels. The related transcription factor SREBP-2 likewise induced PPARgamma expression. In addition, cholesterol depletion, a condition known to result in proteolytic activation of transcription factors of the SREBP family, induced PPARgamma expression and improved PPRE-driven transcription. The effect of the SREBPs on PPARgamma expression was mediated through the PPARgamma1 and -3 promoters. Both promoters contain a consensus E-box motif that mediates the regulation of the PPARgamma gene by ADD-1/SREBP-1 and SREBP-2. These results suggest that PPARgamma expression can be controlled by the SREBP family of transcription factors and demonstrate new interactions between transcription factors that can regulate different pathways of lipid metabolism. 

Retracted: No

PubPeer comments:
 Figure 5A. Much more similar than you would expect. https: imgur.com nVJ8gth , 
 #1 There is nothing to remark in this blot. If you read the paper carefully, you will notice that lanes 1, 4, and 7 are exactly the same sample (although it is not literally stated in the legend of the figure). It corresponds to the binding of SREBP to the PPAR promoter sequence (which is the same control for the whole experiment). Lanes 2-3, 5-6, and 8-9 are a competition experiment using the same oligo, a consensus oligo, or a mutated version of the oligo respectively. Indeed, the figure could have been done without lanes 4 and 7, which were added to help compare with the following lanes. So the similarity makes sense, right? Hope this helps , 
 THESE ARE NOT THE SAME IMAGES. Please consider zooming in the images and you will see hundreds of differences. Some examples here ![file] , 
 #2 Your explanation does not help really. Same sample loaded 3 times should not give images which share many features. The images are low resolution so you wouldn t expect themt o look exactly the same. , 
 Good morning, This is Lluis Fajas, the first author of this paper. Please find the original autoradiography of the gel shift. Notice that lane 4 has been spliced out to keep the coherence of the competition with the other conditions. The blot has been stretched vertically.![file] , 
 Hi again, I also found a second in dependentr experiment of this competition assay. ![file] ,