Transcriptional Control of Liver Development

描述（由申请人提供）： 肝脏由腹前肠内胚层的细胞发育而成，这些细胞分化成肝母细胞并增殖到邻近的间充质中形成肝芽。这些细胞中的大多数成熟为肝细胞，但门静脉周围的一些细胞发育为胆管板，从而产生胆管。在小鼠中，随后形成肝动脉，从而完成门静脉三联体。肝脏发生缺陷是导致多种儿科肝脏疾病的原因。该提案旨在培训主要研究者（PI）从事研究职业，专注于肝脏发育的研究，最终目的是改善这些和其他肝脏疾病。 特异性目的1-3的目的是表征控制肝发生的调控网络。有翼螺旋转录因子的Foxa家族在肝发生开始之前立即在内胚层中表达，并且它们结合到许多肝特异性基因的调控区。第一个特定的目的测试了Foxa 1和Foxa 2在肝脏的特化和进一步发育中发挥核心作用的假设。将产生整个内胚层缺乏Foxa 1和Foxa 2的小鼠胚胎;初步结果表明，在不存在这些因子的情况下，不会发生肝特化。Foxa在肝脏发育中的作用机制将使用蛋白质和mRNA检测技术来探索，以确定其表达依赖于Foxa 1或Foxa 2的肝脏转录因子。在第二个具体目标，这些发现将扩展使用染色质免疫沉淀结合启动子微阵列分析，以确定新的Foxa 1和Foxa 2靶基因。第三个具体的目标将扩大重点，包括胆管和肝动脉发育的后期阶段，通过衍生的转基因小鼠系，允许导管板和胆管上皮细胞特异性基因表达的分析。这些数据将用于检验肝动脉生成需要来自发育中的胆管的诱导信号的假设。 在这些研究过程中，PI将获得实验室技能、研究培训和关键试剂，这将使他能够开始作为独立的物理学家-科学家工作。从这次和未来的研究中获得的信息将提高我们对肝脏发育的理解，并可能提高人类肝脏疾病的诊断，治疗和预防。

DESCRIPTION (provided by applicant): The liver develops from cells of the ventral foregut endoderm which differentiate into heptoblasts and proliferate into the adjacent mesenchyme to form the liver bud. Most of these cells mature into hepatocytes, but some of those surrounding the portal veins develop into the ductal plate, which gives rise to the bile ducts. In mice, this is followed by the formation of the hepatic arteries, thereby completing the portal triad. Defects in hepatogenesis are responsible for several pediatric liver diseases. This proposal aims to train the principal investigator (PI) for a research career focused on the study of liver development with the ultimate purpose of ameliorating these and other liver disorders. The goal of Specific Aims 1-3 is to characterize the regulatory networks controlling hepatogenesis. The Foxa family of winged helix transcription factors is expressed in the endoderm immediately before the onset of hepatogenesis, and they bind to the regulatory regions of a number of liver-specific genes. The first specific aim tests the hypothesis that Foxa1 and Foxa2 play a central role in the specification and further development of the liver. Mouse embryos lacking Foxa1 and Foxa2 throughout the endoderm will be generated; preliminary results indicate that in the absence of these factors, hepatic specification does not occur. The mechanism of Foxa function in liver development will be explored using protein and mRNA detection techniques to identify liver transcription factors whose expression is dependent on Foxa1 or Foxa2. In the second specific aim, these findings will be extended using chromatin immunoprecipitation combined with promoter microarray analysis to identify novel Foxa1 and Foxa2 target genes. The third specific aim will expand the focus to include the later stages of bile duct and hepatic artery development through the derivation of a transgenic mouse line allowing the analysis of ductal plate and biliary epithelial cell-specific gene expression. This data will be used to test the hypothesis that hepatic arteriogenesis requires inductive signals from developing bile ducts. Over the course of these studies, the PI will acquire laboratory skills, research training, and critical reagents which will enable him to begin work as an independent physician-scientist. The information which will be obtained from this and future investigations will improve our understanding of liver development and may enhance the diagnosis, treatment, and prevention of liver disease in humans.