35. Cinti S, Eberbach S, Castellucci M, Accili D (1998) Lack of insulin receptors affects the formation of white adipose tissue in mice. A morphometric and ultrastructural analysis. Diabetologia 41: 171–177. 36. Simon J, Leclercq B (1985) Fat and lean chickens: prefattening period and in vivo sensitivity to insulin, atropine, and propranolol. Am J Physiol 249: R393– 401. 37. Xu G, Stoffers DA, Habener JF, Bonner-Weir S (1999) Exendin-4 stimulates both beta-cell replication and neogenesis, resulting in increased beta-cell mass and improved glucose tolerance in diabetic rats. Diabetes 48: 2270–2276. 38. Suarez-Pinzon WL, Yan Y, Power R, Brand SJ, Rabinovitch A (2005) Combination therapy with epidermal growth factor and gastrin increases beta- cell mass and reverses hyperglycemia in diabetic NOD mice. Diabetes 54: 2596– 2601. 39. Nielsen JH, Galsgaard ED, Moldrup A, Friedrichsen BN, Billestrup N, et al. (2001) Regulation of beta-cell mass by hormones and growth factors. Diabetes 50 Suppl 1:: S25–29. 40. Gupta RK, Gao N, Gorski RK, White P, Hardy OT, et al. (2007) Expansion of adult beta-cell mass in response to increased metabolic demand is dependent on HNF-4alpha. Genes Dev 21: 756–769. 41. Heit JJ, Apelqvist AA, Gu X, Winslow MM, Neilson JR, et al. (2006) Calcineurin/NFAT signalling regulates pancreatic beta-cell growth and function. Nature 443: 345–349. Role of Wdr13 Gene in Beta Cell Proliferation 42. Rulifson IC, Karnik SK, Heiser PW, ten Berge D, Chen H, et al. (2007) Wnt signaling regulates pancreatic beta cell proliferation. Proc Natl Acad Sci U S A 104: 6247–6252. 43. Nikolova G, Jabs N, Konstantinova I, Domogatskaya A, Tryggvason K, et al. (2006) The vascular basement membrane: a niche for insulin gene expression and Beta cell proliferation. Dev Cell 10: 397–405. 44. Cozar-Castellano I, Weinstock M, Haught M, Velazquez-Garcia S, Sipula D, et al. (2006) Evaluation of beta-cell replication in mice transgenic for hepatocyte growth factor and placental lactogen: comprehensive characterization of the G1/S regulatory proteins reveals unique involvement of p21cip. Diabetes 55: 70–77. 45. Cozar-Castellano I, Haught M, Stewart AF (2006) The cell cycle inhibitory protein p21cip is not essential for maintaining beta-cell cycle arrest or beta-cell function in vivo. Diabetes 55: 3271–3278. 46. Nagy A, Rossant J, Nagy R, Abramow-Newerly W, Roder JC (1993) Derivation of completely cell culture-derived mice from early-passage embryonic stem cells. Proc Natl Acad Sci U S A 90: 8424–8428. 47. He TC, Zhou S, da Costa LT, Yu J, Kinzler KW, et al. (1998) A simplified system for generating recombinant adenoviruses. Proc Natl Acad Sci U S A 95: 2509–2514. 48. Meng ZX, Nie J, Ling JJ, Sun JX, Zhu YX, et al. (2009) Activation of liver X receptors inhibits pancreatic islet beta cell proliferation through cell cycle arrest. Diabetologia 52: 125–135. PLoS ONE | www.plosone.org 10 June 2012 | Volume 7 | Issue 6 | e38685