Human RETN lacks a functional PPARγ-binding site.
A, sequence alignment of the mouse, rat, and human resistin genes
based on comparative genomic analysis. Sequence coordinates are relative to
the resistin TSS for each species. C/EBP and PPARγ motifs from the mouse
adipocyte enhancer are underlined. B, EMSA examining binding
of in vitro translated PPARγ/RXRα to the mouse
PPARγ-binding site (mouse) or the corresponding region of human
RETN (human). C, luciferase activity of transfected
plasmids in 293T cells. The human sequence corresponding to the mouse enhancer
(–13262 to –13110 bp, hRETN-Enh) is fused to a luciferase
reporter vector and cotransfected with or without C/EBPα and
PPARγ/RXRα expression vectors. D, luciferase activity of
transfected plasmids in 3T3-L1 adipocytes. Reporter gene expression is driven
by the mouse enhancer (–8843 to –8695 bp, mRetn-EnhC) or
the corresponding sequence of human RETN (hRETN-Enh).