Skip to main content
. 2012 Apr;53(4):755–766. doi: 10.1194/jlr.M022178

Fig. 7.

Fig. 7.

Hypothetical model: binding dynamics of three transcription factors (Kr-pok, SREBP-1c, and Sp1) on the SRE/E-box of the FASN gene promoter. A: Sp1 is abundant, whereas SREBP-1c was not induced and is scarce. The promoter elements are mainly bound by Sp1, and transcription is at a basal level. B: Upon induction of SREBP-1c, Sp1 binding is reduced and SREBP-1c binding is increased, resulting in potent transcriptional activation. C: Upon induction of Kr-pok, Sp1 binding is induced and SREBP-1c binding is reduced. Kr-pok did not directly bind to the promoter, and Kr-pok had little effect on transcription. D: Synergistic activation of FASN gene transcription by Kr-pok and SREBP-1c. In the presence of high levels of Kr-pok and SREBP-1c, binding of SREBP-1c decreased compared with that of (B), and Sp1 binding decreased compared with that of (C). However, unlike (B) or (C), SREBP-1c and Sp1 binding are maintained at certain level that allows for the synergistic activation of FASN gene transcription. Arrows represent DNA-protein interactions. The thickness of the arrow indicates relative binding activity. Tss (+1), transcription start site.