The role of Gata 4 in exocrine pancreas development

描述(申请人提供)：本研究的最终目的是阐明外分泌胰腺特化和分化的分子调控。最近在理解胰腺前体细胞如何选择产生外分泌和内分泌细胞命运方面取得了进展。然而，一旦做出了最初的命运决定，控制外分泌指定和分化的分子事件在很大程度上是未知的。目前，我们只知道一个调节因子，P48，它对于分化的外分泌细胞的产生是至关重要的。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一个复杂的调节因子网络。我们最近确定了GATA4，一种锌指转录调控因子，在前肠内胚层区域表达，产生胰腺，后来限制在外分泌腺泡细胞，在那里它与P48物理上相互作用。我们推测Gata4在胰腺外分泌的分化和发育中起关键作用。为了验证这一假说，我们建议进一步表征Gata4在胚胎胰腺发育过程中的表达，并确定其在胰腺外分泌发育和分化中的功能。本研究的具体目的是：1.明确Gata4在发育中的外分泌胰腺中的表达模式。我们将准确地确定Gata4在胚胎胰腺中表达的时间和地点，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之间的物理相互作用，P48是一种重要的胰腺外分泌蛋白。我们还将确定Gata4调节已知外分泌基因的能力，这些外分泌基因在其启动子区域中包含GATA和P48结合位点。3.鉴定和鉴定Gata4在胰腺外分泌发育中的作用。我们将在原代细胞培养和AR42J细胞中使用反义技术来检测Gata4缺失对胰腺外分泌发育的影响。4.体内研究Gata4在胰腺外分泌分化中的作用。

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.