The role of Gata 4 in exocrine pancreas development

描述（由申请人提供）：本研究的最终目的是阐明胰腺外分泌特化和分化的分子调控。最近的进展已经在理解胰腺祖细胞如何选择引起外分泌与内分泌细胞的命运。然而，一旦最初的命运决定已经作出，控制外分泌规格和分化的分子事件在很大程度上是未知的。目前，我们只知道一个单一的调节因子，p48，这是至关重要的分化外分泌细胞的产生所需的。与许多其他发育系统一样，指导外分泌胰腺发育和分化的分子机制可能涉及复杂的调控因子网络。我们最近已经确定，Gata4，锌指转录调控因子在前肠内胚层的区域中表达，该区域产生胰腺，后来被限制在外分泌腺泡细胞中，在那里它与p48发生物理相互作用。我们推测Gata4在外分泌胰腺的分化和发育中起着关键作用。为了验证这一假设，我们建议进一步表征Gata4在胚胎胰腺发育过程中的表达，并确定其在外分泌胰腺发育和分化中的功能。这项建议的具体目标是：1.定义Gata4在发育中的外分泌胰腺中的表达模式。我们将精确确定Gata4在胚胎胰腺中表达的时间和位置，并将其表达模式与已知的胰腺分子标记物进行比较。2.验证和表征Gata4和p48（一种重要的胰腺外分泌蛋白）之间的物理相互作用。我们还将确定Gata4调节已知外分泌基因的能力，所述外分泌基因在其启动子区域内含有加塔和p48结合位点。3.鉴定和表征Gata4在外分泌胰腺发育中的功能。我们将在原代细胞培养物和AR 42 J细胞中使用反义技术来检查Gata4缺失对外分泌胰腺发育的影响。4.确定Gata4在体内胰腺外分泌特化和分化中的功能。

DESCRIPTION (provided by applicant): The ultimate goal of this study is to elucidate the molecular regulation of exocrine pancreas specification and differentiation. Recent advances have been made in understanding how a pancreatic progenitor cell chooses to give rise to an exocrine versus endocrine cell fate. However, once the initial fate decision has been made, the molecular events that control exocrine specification and differentiation are largely unknown. Currently, we are aware of only a single regulatory factor, p48 that is critically required for the generation of differentiated exocrine cells. As in many other developmental systems, the molecular mechanisms that direct the development and differentiation of the exocrine pancreas are likely to involve a complex network of regulatory factors. We have recently determined that Gata4, a zinc-finger transcriptional regulatory factor is expressed in the region of the foregut endoderm that gives rise to pancreas and later becomes restricted to the exocrine acinar cells, where it physically interacts with p48. We hypothesize that Gata4 plays a critical role in the differentiation and development of the exocrine pancreas. To test this hypothesis, we propose to further characterize the expression of Gata4 during embryonic pancreas development and determine its function in the development and differentiation of the exocrine pancreas. The specific aims of this proposal are to: 1. Define the expression pattern of Gata4 in the developing exocrine pancreas. We will determine precisely when and where Gata4 is expressed in the embryonic pancreas and compare its expression patterns to known pancreatic molecular markers. 2. Verify and characterize the physical interaction between Gata4 and p48, an essential exocrine pancreas protein. We will also determine the ability of Gata4 to regulate known exocrine genes that contain Gata and p48 binding sites within in their promoter regions. 3. Identify and characterize the function of Gata4 in exocrine pancreas development. We will use antisense techniques in primary cell cultures and AR42J cells to examine the effects of loss of Gata4 on the development of the exocrine pancreas. 4. Determine the function of Gata4 in exocrine pancreas specification and differentiation in vivo.