IRS-2 FUNCTION IN BETA CELL PHYSIOLOGY

描述：(改编自申请人的摘要)本修订方案是 来自一位知名的调查员，他对 胰岛素的作用领域，现在到了β细胞生理学领域。这 建议基于首席调查员使用以下方法生成的最新数据 IRS1和IRS2联合缺失小鼠的基因消融 IGF-1受体的等位基因。最近发表在《自然》杂志上的这些数据 遗传学，强烈表明IRS2是胰岛β的关键决定因素 细胞发育和β细胞中的IGF-1信号主要是通过 IRS2。这些数据进一步暗示，IGF-1信号通过IRS2作为主要信号 形成最佳组合的β细胞所需的途径。 这个应用程序将扩展这些发现以确定潜在的机制 对于这些假想的关系。第一，组织切片检查 胚胎和成年小鼠的胰腺将被用来检验这一假设 IRS2对胰岛前体细胞的增殖和存活至关重要 确定IRS2蛋白缺失小鼠发育失败的主要部位。 第二，PI-3-激酶在介导IRS2的某些作用中的作用 将检查β细胞的发育情况。第三，开展试点， 确定它是否确实是在β细胞中特别缺乏的IRS2 这会导致IRS2基因敲除小鼠患糖尿病。IRS2将重新引入 这些动物，特别是在β细胞中，及其对糖尿病的影响 监测到了综合症。最后，特异性地干扰IRS2蛋白的表达 在Beta细胞中进行，以确定这是否足以 导致糖尿病，而IRS2的特异性肝脏破坏将作为一种 推定为阴性对照。

DESCRIPTION: (Adapted from the applicant's abstract) This revised proposal is from a well established investigator who has made seminal contributions to the field of insulin action and now to the field of beta cell physiology. This proposal is based on recent data generated by the principal investigator using gene ablation in mice of IRS1 and IRS2, in combination with mice lacking one allele of the IGF-1 receptor. These data, recently published in Nature Genetics, strongly suggest that IRS2 is a key determinant of pancreatic beta cell development and that IGF-1 signaling in beta cells is largely through IRS2. The data further implicate IGF-1 signaling through IRS2 as a primary pathway that is required for an optimal complement of beta cells to develop. This application will extend these findings to determine underlying mechanisms for these hypothetical relationships. First, examination of tissue sections of embryo and adult mouse pancreas will be conducted to test the hypothesis that IRS2 is critical for proliferation and survival of islet precursor cells and identify the major site of developmental failure in mice lacking IRS2 protein. Second, the role of PI 3-kinase in mediating some of the effects of IRS2 in beta cell development will be examined. Third, experiments will be conducted to determine whether it is in fact the IRS2 lacking specifically in beta cells that causes diabetes in IRS2 gene knockout mice. IRS2 will be reintroduced into these animals, specifically in beta cells, and its effect on the diabetes syndrome monitored. Finally, disruption of IRS2 protein expression specifically in beta cells will be conducted to determine whether this is sufficient to cause diabetes, and specific hepatic disruption of IRS2 will be achieved as a presumed negative control.