MAPK8 and obesity due to melanocortin 4 receptor deficiency: Though the previously described JNK-1 conventional knock out mouse replaces exon 2 of JNK-1 with a neo resistance gene [12] and we copied this strategy by flanking exon 2 of JNK-1 with loxP sites, we assessed whether the absence of JNK-1 in the whole body indeed protects from diet-induced obesity and associated disorders.