Targeted disruption of Reg gene : A new animal model of diabetes and pancreatitis.

1.将突变的Reg I基因(外显子2-3替换为新霉素抗性基因)在ES细胞中进行电穿孔，获得突变的Reg I等位基因克隆。一只雄性嵌合体将突变的等位基因传递给它的后代。异种小鼠明显正常，并生下了与突变的Reg I基因位点同源的小鼠。2.Reg I基因缺陷小鼠在包括胰岛β细胞在内的各种组织中未见形态变化。Reg I基因缺陷小鼠的体重、血糖和血清胰岛素水平与正常小鼠基本相同。3.硫代葡萄糖致肥胖小鼠胰岛β细胞增生。经硫代葡萄糖苷处理的REG I缺陷小鼠的胰岛明显小于对照组，表明REG I缺陷小鼠的胰岛在成年后对β细胞增殖的需求具有较低的增殖活性。因此，很有可能作为…提示Reg I基因缺陷小鼠在肥胖时易发生非胰岛素依赖型糖尿病(NIDDM)，是研究肥胖NIDDM发生发展的良好模型。4.在乙硫氨酸诱导的慢性胰腺炎模型中，Reg I基因缺陷小鼠发生重症胰腺炎，且突变小鼠体重低于对照小鼠。这一结果提示，REG I基因参与了慢性胰腺炎的抵抗，REG I基因缺陷小鼠是一种新的慢性胰腺炎模型。我们揭示了所有的小鼠REG基因组成一个多基因家族，REG家族由I、II和III三个亚型组成，并且所有的REG基因都位于染色体6C/D的相邻位置。通过Northern杂交检测了REG家族的其他成员(REG II、REG IIIpha、RegIIIbeta和REG IIIGamma)在小鼠胰腺中的表达，发现在REG I缺陷小鼠中，REG IIIpha和REG IIIGamma的表达增加提示REG I的某些功能可能被残存的REG家族的表达增加所代偿。为了阐明这种可能性，我们现在正在培育缺乏所有REG家族基因的突变小鼠。较少

1.To generate mutant mice lacking Reg I gene, the mutated Reg I gene, in which exon 2-3 was replaced by neomycin resistant gene, was electroporated in ES cells, and an ES cell clone mutated the Reg I allele was obtained. A male chimera transmitted the mutant allele to its offspring. Heterogous mice were apparently normal, and gave birth to mice homologous for mutant Reg I locus.2.Reg I deficient mice showed no morphological changes in various tissues including pancreatic beta cells. Body weight, blood glucose and serum insulin levels in Reg I-deficient mice were almost the same as those in control mice.3.Aurothioglucose treatment induced obesity with hyperplasia of islet beta-cells in control mice. The islets in aurothioglucose-treated Reg I-deficient mice were significantly smaller than those of control, indicating that islets of Reg I-deficient mice have lower proliferation activity in response to a demand of beta-cell proliferation in adulthood. Therefore, it is quite possible to as … More sume that Reg I-deficient mice easily develop non-insulin dependent diabetes mellitus (NIDDM) when they become obese and be a good model for studying development of NIDDM in obesity.4.In the ethionine-induced chronic pancreatitis model, Reg I-deficient mice developed severe pancreatitis and the body weight of the mutant mice was lower than that of control mice. This result suggests that Reg I is involved in resistance of chronic pancreatitis and that Reg I-deficient mice is a new model of chronic pancreatitis.We revealed that all the mouse Reg genes constitute a multigene family, Reg family, which consists of three subtypes (type I,II and III), and that all the Reg genes assigned to the adjacent site of chromosome 6C/D.6.We examined expression of the other members of Reg family (Reg II,Reg IIIalpha, RegIIIbeta and Reg IIIgamma) in mouse pancreas by Northern blot analyzes, and revealed that expressions of Reg IIIalpha and Reg IIIgamma were increased in Reg I-deficient mice, suggesting a possibility that some functions of Reg I were compensated by the increased expression of remnant Reg family. To clarify this possibility, we are now generating mutant mice deficient in all the Reg family genes. Less