BIOLOGY OF THE EMBRYONIC CORNEAL EPITHELIUM

这笔赠款的长期目标是确定功能性和 基底膜、角膜上皮之间的结构关系 细胞骨架和细胞器分布(粗面内质网、高尔基体)。一直以来 已确定培养的细胞在对 含有细胞黏附分子、肌动蛋白的细胞外基质蛋白 相关蛋白、激酶和钙结合蛋白。此外, 细胞黏附分子通过产生酪氨酸作为信号受体 磷酸化，钙离子内流，细胞质pH升高和 磷脂周转。我们将扩展这项先前的工作以确定 这些蛋白质和机制也是重组肌动蛋白所必需的。 胚胎角膜上皮模型。发生的一系列事件 肌动蛋白皮质垫重组过程中对细胞外的反应 基质分子将被解剖以确定它们之间的关系 细胞外基质、细胞黏附分子、细胞骨架和细胞器的分布。 我们将研究以下具体领域和问题：一、细胞-细胞和 角膜上皮发育过程中细胞-基质的相互作用。我们会 检验肌动蛋白皮质重组依赖于 在包括受体结合在内的一系列事件上，肌动蛋白相关 蛋白质重排和信号转导。具体是什么？ 细胞-细胞连接或细胞外基质之间的连接蛋白 受体和肌动蛋白？非肌动蛋白细胞骨架是如何组织起来的 胚胎角膜上皮细胞？是肌动蛋白的重组 皮质垫依赖于信号转导？二、控制因素 角膜分化过程中的mRNA分布。我们已经证明了贝塔- 肌动蛋白mRNA在角膜上皮细胞中呈极化分布，类似于F- 肌动蛋白。特定的胶原蛋白mRNAs似乎也有一个独特的 分布于软骨细胞和角膜上皮细胞。我们将测试 肌动蛋白和胶原mRNA在角膜中有组织的假说 上皮细胞骨架依赖机制及其重组 细胞骨架的变化是上调基质合成的一个因素。多么 细胞是否组织肌动蛋白和胶原蛋白mRNA？将会扰乱 细胞骨架也会破坏胶原基因的分布吗？三、影响因素 肌动蛋白皮质垫过程中细胞器分布的控制 重组。我们之前已经证明，通过 细胞松弛素D引起基底隔区RER减少。 上皮细胞与基膜分离。我们将检验这一假设 细胞骨架元素组织蛋白质分泌细胞器和 翻译辅因子调节分泌蛋白的表达。是 翻译辅因子或依附稳定的内质网 到细胞骨架上吗？是什么机制导致了这种依恋？ 综上所述，角膜上皮相互作用的细胞生物学模型 细胞外环境和细胞组织之间的关系 发展起来的。

The long-term objective of this grant is to determine the functional and structural relationships between the basement membrane, corneal epithelial cytoskeleton and organelle distribution (RER, Golgi). It has been established that cultured cells form focal adhesions in response to extracellar matrix proteins that contain cell adhesion molecules, actin associated proteins, kinases and calcium binding proteins. In addition, cell adhesion molecules act as signaling receptors by causing tyrosine phosphorylation, Ca2+ influx, an increase in cytoplasmic pH and phospholipid turnover. We will expand this previous work to determine if these proteins and mechanisms are also necessary for reorganizing actin in the embryonic corneal epithelial model. The sequence of events that occur during actin cortical mat reorganization in response to extracellular matrix molecules will be dissected to determine the relationships between the ECM, cell adhesion molecules, cytoskeleton and organelle distribution. We will study the following specific areas and questions: I. Cell-cell and cell-matrix interactions during corneal epithelial development. We will test the hypothesis that the reorganization of the actin cortical depends upon a cascade of events including receptor binding, actin associated protein rearrangements, and signal transduction. What are the specific link proteins between cell-cell junctions or extracellular matrix receptors and actin? How is the non-actin cytoskeleton organized in embryonic corneal epithelial cells? Is the reorganization of the actin cortical mat dependent on signal transduction? II. Factors controlling mRNA distribution during corneal differentiation. We have shown that beta- actin mRNA has a polarized distribution in corneal epithelia similar to F- actin protein. Specific collagen mRNAs also appear to have a distinct distribution in chondrocytes and corneal epithelia. We will test the hypothesis that actin and collagen mRNA are organized in the corneal epithelium by a cytoskeletal dependent mechanism and that reorganization of the cytoskeleton is a factor in up-regulating matrix synthesis. How does the cell organize actin and collagen mRNA? Will disruption of the cytoskeleton also disrupt collagen mRNA distribution? III. Factors controlling organelle distribution during actin cortical mat reorganization. We have previously shown that disrupting actin with cytochalasin D caused the RER in the basal compartment to decrease in epithelia isolated with the basal lamina. We will test the hypothesis that cytoskeletal elements organize protein secretion organelles and translation cofactors to regulate expression of secreted proteins. Are translational cofactors or endoplasmic reticulum stabilized by attachment to the cytoskeleton? What mechanisms are responsible for this attachment? In summary, a cell biological model for corneal epithelial interactions between the extracellular environment and cellular organization has been developed.