Figure 5.

Leptin responsiveness maps to a specific region of the hTRH promoter. (a) 293T cells were transfected with a variety of hTRH reporter constructs. Their response to 100 nM leptin was then determined. The data are expressed as relative luciferase activity, and the fold response is indicated above each construct. (b) The promoter sequences of the human, rat, and murine TRH genes are compared in the area of Stat responsiveness. The Stat-responsive element is boldface and located between –141 and –132. The SP-1 site is boldface and underlined and located between –125 and –119. Also shown are the mutations made to create the Statm and ΔSP-1 constructs. (c) 293T cells were transfected with the mTRH reporter construct in an identical paradigm, and its response to leptin was assessed. nTRE, negative thyroid hormone response element.