DEVELOPMENTAL REGULATION OF LACTASE GENE TRANSCRIPTION

描述（摘自申请人摘要） 这项建议的主要目标是促进发展一个 在分子和生物学领域的独立和富有成效的研究者， 胃肠道发育生物学。 长期研究 该提案的目标是了解调节 肠道乳糖酶基因转录的成熟性下降。 肠乳糖酶是肠上皮细胞二糖脱氢酶， 消化乳糖，牛奶中的主要碳水化合物。 乳糖酶活性是 在断奶前达到最大值，然后在成熟过程中显著下降。 乳糖酶活性降低加上牛奶摄入过多导致 大多数成熟哺乳动物碳水化合物吸收不良的症状，包括 人类 参与调节这种成熟下降的机制， 肠乳糖酶活性尚未完全确定。 最近的报告表明，控制乳糖酶的下降主要是 在基因转录水平上。 此外，我们的初步数据显示， 表明乳糖酶启动子顺式元件在 肠成熟至少有两个不同的核蛋白。 我们 基于这些数据的假设是，乳糖酶的成熟下降 表达是由其启动子和 特异性核转录因子。 具体研究目标， 因此，旨在表征乳糖酶基因调控元件 以及鉴定与这些元件相互作用的核蛋白。 我们 目的通过分析乳糖酶DNA调控元件， 与报告基因连接的基因组缺失的表达， 转基因小鼠 我们将鉴定与乳糖酶相互作用的核蛋白 使用DNase I超敏性、足迹和凝胶移位的基因片段 测定。 我们的目标是通过改变它们的功能来表征蛋白质。 在细胞培养物和转基因小鼠中的表达， 转录活性 候选人，划定了一个研究领域的调查，将进行 在导师的建议和指导下进行研究， 发育生物学 研究经验，辅以 分子和发展领域的课程和研讨会 生物学，将为候选人提供过渡到一个 职业生涯作为一个独立的和富有成效的科学家进行研究的 肠道发育的分子生物学

DESCRIPTION (Taken from the applicant's Abstract) The broad objective of this proposal is to foster the development of an independent and productive investigator in the area of molecular and developmental biology of the gastrointestinal tract. The long term research goal of this proposal is to understand the molecular mechanisms regulating the maturational decline in intestinal lactase gene transcription. Intestinal lactase is the enterocyte disaccharidase responsible for digestion of lactose, the primary carbohydrate in milk. Lactase activity is maximal prior to weaning and then declines significantly during maturation. Decreased lactase activity combined with excessive milk consumption results in symptoms of carbohydrate malabsorption in most mature mammals, including humans. The mechanisms involved in regulating this maturational decline in intestinal lactase activity have not been fully defined. Recent reports suggest that control of the decline in lactase is primarily at the level of gene transcription. In addition, our preliminary data suggest that a lactase promoter cis element is bound differentially during intestinal maturation by at least two distinct nuclear proteins. Our hypothesis, based on this data, is that the maturational decline in lactase expression is mediated by differential interaction between its promoter and specific nuclear transcription factors. Specific research objectives, therefore, are aimed at characterization of lactase gene regulatory elements and identification of nuclear proteins interacting with those elements. We aim to characterize the lactase DNA regulatory elements by analyzing expression of genomic deletions linked to a reporter gene and expressed in transgenic mice. We will identify nuclear proteins interacting with lactase gene fragments using DNase I hypersensitivity, footprint, and gel shift assays. We aim to functionally characterize the proteins by altering their expression in cell culture and in transgenic mice and assaying for transcriptional activity. The candidate, having delineated an area of research inquiry, will conduct the research with the advice and guidance of a mentor in the field of developmental biology. The research experience, supplemented with coursework and seminars in the fields of molecular and developmental biology, will provide the candidate with the tools needed to transition to a career as an independent and productive scientist performing research on the molecular biology of intestinal development.