Role of CTCF in EGF-Induced Corneal Epithelial Growth

CTCF 在 EGF 诱导的角膜上皮生长中的作用

• 批准号: 7014001
• 负责人: LUO LU
• 金额: $ 29万
• 依托单位: LUNDQUIST INSTITUTE FOR BIOMEDICAL INNOVATION AT HARBOR-UCLA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-02-01 至 2008-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7014001
• 关键词: RNA; RNA interference; SDS polyacrylamide gel electrophoresis; biological signal transduction; cell cycle; cell growth regulation; cell line; cell proliferation; confocal scanning microscopy; corneal epithelium; epidermal growth factor; flow cytometry; gel mobility shift assay; gene expression; genetic transcription; human tissue; mitogen activated protein kinase; northern blottings; nuclear proteins; polymerase chain reaction; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant): The long-term goal of the present study is to investigate growth factor-regulated cell proliferation during the corneal epithelial renewal process and wound healing. We recently found that CTCF, an important nuclear protein that binds to CCCTC sequence, activated by epidermal growth factor (EGF) mediates the regulation of homeobox Pax6 gene expression. Undoubtedly, EGF-induced activation of CTCF controlling Pax6 expression plays a central role in regulation of proliferation/differentiation during corneal epithelial renewal and wound healing. We also found in corneal epithelial cells that EGF regulates CTCF expression and phosphorylation through the Erk (MAP kinase) signaling pathway. CTCF functions as a repressor in regulating expression of Pax6 gene by interacting with a specific element in the 5' flanking region upstream from the Pax6 P0 promoter. Our results strongly support the notion that EGF-induced corneal epithelial proliferation requires the activation of CTCF whereas Pax6 activity has to be inhibited because it has been suggested that Pax6 may promote corneal epithelial cell early differentiation. We hypothesize that the effectiveness of EGF-induced corneal epithelial cell proliferation is dependent on the ability of the growth factor to increase CTCF activity and to decrease Pax6 gene expression. To test this hypothesis, we will undertake three specific aims including: 1) investigation of the effects of EGF-induced CTCF activation and Pax6 suppression on cell proliferation, 2) delineation of the interaction between Erk and CTCF that enables EGF to regulate CTCF activity, and 3) elucidation of the regulatory mechanism that enables CTCF to regulate Pax6 gene expression. Such studies will provide the first step towards testing the physiological significance of CTCF in mediating growth factor-induced corneal epithelial cell proliferation. In addition, the results will also reveal novel regulatory mechanisms that describe why Pax6 is retained in the mature corneal epithelia and how Pax6 expression affects corneal epithelial cell fate. Furthermore, the new insights will be obtained into the mechanisms that mediate growth factor control of cellular proliferation and differentiation.

描述（由申请人提供）：本研究的长期目标是研究角膜上皮更新过程和伤口愈合过程中生长因子调节的细胞增殖。我们最近发现 CTCF 是一种与 CCCTC 序列结合的重要核蛋白，由表皮生长因子 (EGF) 激活，介导同源盒 Pax6 基因表达的调节。毫无疑问，EGF 诱导的 CTCF 激活控制 Pax6 表达，在角膜上皮更新和伤口愈合过程中的增殖/分化调节中发挥核心作用。我们还在角膜上皮细胞中发现EGF通过Erk（MAP激酶）信号通路调节CTCF的表达和磷酸化。 CTCF 通过与 Pax6 P0 启动子上游 5' 侧翼区域中的特定元件相互作用，充当调节 Pax6 基因表达的阻遏蛋白。我们的结果强烈支持这样的观点，即EGF诱导的角膜上皮增殖需要CTCF的激活，而Pax6活性必须受到抑制，因为有人认为Pax6可能促进角膜上皮细胞早期分化。我们假设 EGF 诱导的角膜上皮细胞增殖的有效性取决于生长因子增加 CTCF 活性和降低 Pax6 基因表达的能力。为了检验这一假设，我们将实现三个具体目标，包括：1）研究 EGF 诱导的 CTCF 激活和 Pax6 抑制对细胞增殖的影响，2）描述 Erk 和 CTCF 之间的相互作用，使 EGF 能够调节 CTCF 活性， 3）阐明CTCF调节Pax6基因表达的调节机制。此类研究将为测试 CTCF 在介导生长因子诱导的角膜上皮细胞增殖中的生理意义迈出第一步。此外，结果还将揭示新的调控机制，描述为什么Pax6保留在成熟的角膜上皮中，以及Pax6的表达如何影响角膜上皮细胞的命运。此外，还将获得对介导生长因子控制细胞增殖和分化的机制的新见解。