Gene expression in the mammalian intestine

人类胃肠（GI）道的常见病症，包括先天性畸形、炎性 肠、腹腔和消化性溃疡疾病、胃肠道特异性感染和癌症导致相当高的发病率 和死亡率。尽管许多这些疾病的病理生理学可能与 正常肠道发育机制的基本途径，细胞分化的分子调控， 哺乳动物肠道的胎儿发育知之甚少。这对于分子基础来说尤其如此 肠上皮细胞和其下面的间充质之间的相互作用，一个关键的调节肠道 发育和体内平衡。这项建议旨在利用最新的技术进步， 哺乳动物肠道发育和器官发生的系统分子分析;目标和 实验方法与RFA #DK-01-023的概要密切一致。我们将开始检查 在13和15之间的关键间隔期间基因转录谱的定量和定性变化 在小鼠妊娠期，当肠道内胚层经历一个重要的细胞过渡，从一个贫穷的， 分化的假复层组织形成原始绒毛上皮。初步分析了两个单独的系列 从这些发育阶段制备的基因表达（SAGE）库分析统计显示 令人惊讶的是，少数基因的表达水平发生了显着变化，包括几个假定的 调节细胞间通讯、基因转录和细胞内信号传导。其中一些变化 被认为是驱动获得细胞的命运和形态和组织的形式和功能， 小肠发育该项目的具体目标包括更详细地描述这些SAGE 图书馆，该领域的独特资源，特别着眼于确定一些早期的关键监管机构， 肠上皮分化和间充质-上皮相互作用。我们进一步建议研究 预测在细胞间相互作用中起作用的基因的mRNA表达位点，因此开始绘制关键的 肠道发育中的候选信号通路作为开发实用策略以检查基因的前奏 功能更直接。最后，我们将通过研究动态，在空间和时间上扩展这种分析。 在小肠发育的另外两个阶段，以及在小肠发育的平行阶段， 胃和结肠的发育。对哺乳动物肠道发育的综合分析， 很可能是第一次，将阐明正常发育过程的一些基本方面， 应该有助于改善对胃肠道常见疾病的理解和治疗。

Common disorders of the human gastrointestinal (Gl) tract, including congenital malformations, inflammatory bowel, celiac and peptic ulcer disease, intestine-specific infections and cancer, result in considerable morbidity and mortality in the United States. Although the pathophysiology of many of these disorders is likely related in fundamental ways to mechanisms of normal gut development, the molecular regulation of cell differentiation and fetal development of the mammalian intestine is poorly understood. This is particularly true for the molecular basis of the interaction between gut epithelium and its underlying mesenchyme, a key regulator of intestinal development and homeostasis. This proposal seeks to exploit recent technological advances to initiate a systematic molecular analysis of mammalian intestinal development and organogenesis; the goals and experimental methods are closely aligned with the outline of RFA #DK-01-023. We will begin by examining quantitative and qualitative changes in the gene transcription profile during the critical interval between 13 and 15 days in mouse gestation, when the gut endoderm undergoes an important cellular transition from a poorly differentiated, pseudostratified tissue into a primitive villous epithelium. Preliminary analysis of two separate Serial Analysis of Gene Expression (SAGE) libraries prepared from these developmental stages reveals statistically significant changes in the expression levels of a surprisingly small number of genes, including several putative regulators of intercellular communication, gene transcription, and intracellular signaling. Some of these changes are presumed to drive the acquisition of cellular fate and morphology and tissue form and function in the developing small bowel. The Specific Aims of the project involve more detailed characterization of these SAGE libraries, a unique resource in the field, with a special view toward identifying some of the critical regulators of early intestinal epithelial differentiation and mesenchymal-epithelial interactions. We further propose to examine the sites of mRNA expression for genes predicted to function in intercellular interactions and hence begin to map key candidate signaling pathways in gut development as a prelude to developing practical strategies to examine gene function more directly. Finally, we will expand this analysis in space and in time, by investigating the dynamic alterations in gene expression at two additional stages in small bowel development, and at parallel stages in development of the stomach and colon. The resulting comprehensive analysis of mammalian gut development, quite possibly the first of its kind, will elucidate some essential aspects of normal developmental processes and should contribute to improved understanding and treatment of common disorders of the Gl tract.