An additional parallel with Sirt1 is seen in our tissue-specific studies, where we show that sir2 function is necessary and sufficient in the fat body to maintain insulin signaling and suppress hyperglycemia and obesity, analogous to the role of Sirt1 in the liver and white adipose [9, 13, 24]. The gene discussed is SIRT1; the disease is obesity due to melanocortin 4 receptor deficiency.