ROLE OF HLX IN MOUSE GASTROINTESTINAL/LIVER DEVELOPMENT

HLX 在小鼠胃肠/肝脏发育中的作用

• 批准号: 6380163
• 负责人: MICHAEL D. BATES
• 金额: $ 11.92万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-15 至 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6380163
• 关键词: developmental genetics; gene expression; genetic regulatory element; genetically modified animals; histogenesis; in situ hybridization; intestines; laboratory mouse; liver; microarray technology; neurogenesis; transcription factor

An important goal of developmental biology is the elucidation of the genetic programs that control organogenesis. Little is known about the genetic programs required for mesenchymal interactions with epithelial or neuronal cells in development, particularly as they relate to the formation of organs of the digestive system. Recent studies on Hlx, a gene encoding a homeobox transcription factor, suggest that this gene plays an important role in development and growth of the digestive system. Hlx is expressed in mesenchymal cells of the developing mouse gastrointestinal system. Targeted inactivation of this gene resulted in an embryonic lethal phenotype in which the intestine and liver are present but do not grow. The overarching hypothesis of this proposal is that the specific expression of Hlx protein in mesenchyme results in regulation of the development of the intestine and liver by regulating the expression of genes encoding proteins participating in interactions of mesenchyme with other tissues. In order to determine the role of Hlx in development of the intestine and liver, and to help define the genetic program controlling formation of these organs, three specific aims are proposed. First, it is proposed to identify cis-regulatory elements and trans-activating factors regulating Hlx expression in developing mesenchyme. Segments of the Hlx 5' flanking region which regulate reporter gene expression in cell lines in a manner expected for that of the Hlx promoter have already been identified. It is proposed to evaluate these regions further using reporter constructs (in cell lines and transgenic mice) and biochemical methods. The second specific aim is to test several candidate downstream target genes by comparing their expression in wild-type and Hlx knockout embryos. In the third specific aim, we propose to identify genes regulated by Hlx using Hlx-/-mesenchymal cell lines in which Hlx is present and absent. Hlx will be added to these cells using an inducible expression system or using a retroviral vector. Genes differentially expressed will be identified using microarray techniques. The principal investigator is a pediatric gastroenterologist with significant prior research experience (including a Ph.D.), who is developing a research program in the molecular developmental biology of the digestive system. A Research Career Award will provide the opportunity for mentored development of this program in a rigorous scientific environment. This program will allow additional training in molecular and cellular techniques, development of supervisory skills, and further instruction in the responsible conduct of research.

发育生物学的一个重要目标是阐明控制器官发生的遗传程序。 很少有人知道的遗传程序所需的间充质相互作用与上皮细胞或神经元细胞的发展，特别是因为它们涉及到消化系统的器官的形成。Hlx基因是一个同源异型盒转录因子，近年来的研究表明，该基因在消化系统的发育和生长中起着重要作用。 Hlx在发育中的小鼠胃肠系统的间充质细胞中表达。 该基因的靶向失活导致胚胎致死表型，其中肠和肝存在但不生长。 该提议的首要假设是，Hlx蛋白在间充质中的特异性表达通过调节编码参与间充质与其他组织相互作用的蛋白质的基因的表达而导致肠和肝的发育的调节。 为了确定Hlx在肠和肝脏发育中的作用，并帮助定义控制这些器官形成的遗传程序，提出了三个具体目标。 首先，它提出了确定顺式调控元件和反式激活因子调节Hlx表达在发展间充质。 已经鉴定了Hlx 5'侧翼区的片段，其以预期的Hlx启动子的方式调节细胞系中报告基因的表达。 建议使用报告构建体（在细胞系和转基因小鼠中）和生物化学方法进一步评估这些区域。 第二个具体目的是通过比较它们在野生型和Hlx敲除胚胎中的表达来测试几个候选下游靶基因。在第三个具体的目标，我们建议使用Hlx-/-间充质细胞系，其中Hlx是存在和不存在的，以确定由Hlx调控的基因。 将使用诱导型表达系统或使用逆转录病毒载体将Hlx添加到这些细胞中。 将使用微阵列技术鉴定差异表达的基因。 主要研究者是一名儿科胃肠病学家，具有丰富的既往研究经验（包括博士学位），他正在开发一个消化系统分子发育生物学的研究项目。 研究职业奖将提供在严格的科学环境中指导该计划发展的机会。该计划将允许在分子和细胞技术，监督技能的发展，并在负责任的研究行为的进一步指导额外的培训。