HOMEODOMAIN GENES IN INTESTINAL DEVELOPMENT

描述(摘自申请者摘要)：上皮衬里 哺乳动物的肠道是从一根简单的 胚胎内胚层经历了复杂的形态变化过程 和基因表达。然而，人们对这种分子知之甚少。 指导和整合发展转型的机制 导致成体肠道上皮的成熟形态。 通过表达克隆，申请人已经鉴定出一个编码 一种与转录有高亲和力并能激活转录的蛋白质 肠道特异的DNA调控元件。编码的蛋白质 此cdna是与尾部相关的同源结构域家族的成员。 转录因子(CDX)：同源结构域蛋白至关重要 在整个胚胎发生过程中的发育过程 和器官发生。这一提议是基于CDX的假设 基因对于指导胚胎的发育和分化非常重要。 小鼠肠上皮细胞。因此，这一总体目标是 应用研究CDX基因在肠道中的作用 器官发生和分化。为了实现这一目标，第一个目标 是克隆CDX同源结构域基因家族的成员 在肠道发育过程中的表达，并分析其特征 表达的时间和细胞模式。克隆将是 通过使用RNA的快速DNA末端扩增(RACE)程序实现的 从发育中的小肠和结肠及其表达模式 用原位杂交技术在发育中的肠道进行检测 和免疫组织化学。第二个目的是检查功能 CDX基因在肠上皮细胞分化中的作用 肠道细胞系。几个细胞系是从 肠道组织或结肠癌，随着功能的获得而丧失 CDX基因的功能。第三个目标是检查功能 CDX基因在消化道发育中的作用 老鼠。将进行功能获得和功能丧失的研究 利用绒毛蛋白基因启动子在转基因小鼠中表达 包含CDX基因编码区的构建及其对 将对发展进行评估。该战略将允许进行评估 CDX基因的过早和异位表达在卵巢癌中的作用 完好无损的老鼠。

DESCRIPTION (Adapted from Applicants' Abstract): The epithelial lining of the mammalian intestinal tract develops from a simple tube of embryonic endoderm through a complex process of changes in morphology and gene expression. However, little is known about the molecular mechanisms that direct and integrate the developmental transitions leading to the mature configuration of the adult intestinal epithelium. Using expression cloning, the applicant has identified a cDNA encoding a protein that binds with high affinity to, and activates transcription of, an intestine-specific DNA regulatory element. The protein encoded by this cDNA is a member of the caudal-related homeodomain family of transcription factors (Cdx): homeodomain proteins are central importance in may organisms for developmental processes throughout embryogenesis and organogenesis. This proposal is based on the hypothesis that Cdx genes are important for directing development and differentiation of the mouse intestinal epithelim. Therefore, the overall goal of this application is to investigate the role of Cdx genes in intestinal organogenesis and differentiation. To achieve this goal, the first aim is to clone members of the Cdx family of homeodomain genes that are expressed during intestinal developmental and to characterize their temporal and cellular patterns of expression. The clonings will be achieved by Rapid Amplification of cDNA Ends (RACE) procedure using RNA from developing small intestine and colon and the patterns of expression examined in the developing intestinal tract using in situ hybridization and immunohistochemistry.The second aim is to examine the functional role of Cdx genes in differentiation of the intestinal epithelium using intestinal cell lines. Several cell lines that have been derived from intestinal tissue or colon carcinomas, as the gain of function and loss of function of Cdx genes. The third aim is to examine the functional role of Cdx genes ind development of digestive tract using the transgenic mice. Gain of function and loss of function studies will be performed in transgenic mice using the promoter of the villin gene to express constructs that contain coding regions for Cdx genes and the effect on development will be evaluated. The strategy will allow an assessment of the effect of premature and ectopic expression of Cdx genes in the intact mouse.