To investigate whether GC-inducible KLF9 in macrophages promotes obesity, we generated Rosa26-Klf9flox/flox (R-loxP) mice with an insertion of the CAG-LoxP-Stop-Loxp-Klf9 cassette into the mouse Rosa26 locus (Klf9 knockin mice). The gene discussed is KLF9; the disease is obesity due to melanocortin 4 receptor deficiency.