Mechanism of MEK Kinase 1 in Mouse Eyelid Development

MEK激酶1在小鼠眼睑发育中的作用机制

• 批准号: 6707297
• 负责人: YING XIA
• 金额: $ 34.54万
• 依托单位: UNIVERSITY OF CINCINNATI
• 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 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6707297
• 关键词: JUN kinase; SDS polyacrylamide gel electrophoresis; actins; biological signal transduction; cell migration; cell proliferation; congenital eye disorder; eyelids; gene expression; gene targeting; genetically modified animals; histogenesis; keratinocyte; laboratory mouse; mass spectrometry; microarray technology; microscopy; mitogen activated protein kinase; phosphorylation; transcription factor; western blottings

DESCRIPTION (provided by applicant): The long-term goal of the proposed study is to elucidate the molecular mechanisms by which signal transduction pathways regulate eye development and ocular surface morphogenesis. Embryonic eyelid closure is essential for normal vertebrate ocular surface morphogenesis; its deficiency in mouse results in eyes open at birth (EOB) and various eye pathologies. Many human congenital diseases, such as conjunctiva-corneal dystrophy, ptosis and microophthalmia, exhibit similarities to pathologies found in mice with EOB and are possibly linked to failure in eyelid development. Understanding the molecular events in eyelid closure may uncover the causes of congenital eye diseases, help develop diagnostic tools and identify targets for possible pharmaceutical intervention. Ablation in mice of the Mekkl gene, encoding a cytoplasmic protein kinase, causes EOB phenotype. MEKK1 ablation results in defects in F-actin formation in developing eyelid epithelium and impairments in keratinocyte cell migration. MEKK1-mediated Jun N-terminal kinase (JNK) cascade leads to phosphorylation of the transcription factor cJun and a concomitant change in gene expression pattern that promotes cell movement and proliferation, but prevents epithelium terminal differentiation. These findings lead to the hypothesis that induction of the MEKK1 pathway in the developing eyelid leads to phosphorylation and activation of members of the AP-1 transcription complex, responsible for changes in gene expression, epithelial cell migration and embryonic eyelid closure. The studies proposed in this application will utilize developing eyelid tissues and cultured keratinoctyes from wild type and Mekk1-/-mice available in our laboratory to investigate the molecular pathways involved in the induction of MEKK1 activity and the regulation of AP-1 function. I propose (1) to elucidate the molecular processes of MEKK1 signaling that lead to keratinocyte migration and mediate eyelid closure; (2) to identify the MEKK1-dependent phosphorylation of AP-1 critical for keratinocyte migration; and (3) to define the role of MEKK1 in the regulation of AP-1 transcription functions pertinent to changes in gene expression during eyelid closure. Results from this work will extend our understanding of the molecular regulation of eyelid development and advance our knowledge on the signaling networks and molecular events critical for epithelial cell migration and eyelid closure.

描述（由申请人提供）：拟议研究的长期目标是阐明信号转导途径调节眼睛发育和眼表形态发生的分子机制。胚胎眼睑闭合对于正常的脊椎动物眼表形态发生至关重要。它的小鼠缺乏会导致眼睛在出生时睁开（EOB）和各种眼科病理。许多人类先天性疾病，例如结膜疾病营养不良，ptosis和Microphthalmia，与EOB小鼠中发现的病理相似，并且可能与眼睑发育中的失败有关。了解眼睑闭合中的分子事件可能会发现先天性眼部疾病的原因，有助于开发诊断工具并确定可能的药物干预措施。在MEKKL基因的小鼠中消融，编码细胞质蛋白激酶，导致EOB表型。 MEKK1消融会导致F-肌动蛋白形成的缺陷在发育的眼睑上皮和角质形成细胞迁移中的损伤中。 MEKK1介导的Jun N末端激酶（JNK）级联反应导致转录因子CJUN的磷酸化，并且基因表达模式的伴随变化可促进细胞运动和增殖，但可以防止上皮末端分化。这些发现导致了以下假设：在发育中的眼睑中诱导MEKK1途径会导致AP-1转录复合物的磷酸化和激活，导致基因表达，上皮细胞迁移和胚胎眼睑闭合的变化。该应用中提出的研究将利用来自野生型和MEKK1 - / - 小鼠的眼睑组织和培养的角裂菌，以研究参与MEKK1活性诱导的分子途径以及AP-1功能的调节。我建议（1）阐明导致角质形成细胞迁移并介导眼睑闭合的MEKK1信号的分子过程； （2）确定AP-1的MEKK1依赖性磷酸化对角质形成细胞迁移至关重要； （3）定义MEKK1在与眼睑闭合过程中基因表达变化有关的AP-1转录功能中的作用。这项工作的结果将扩展我们对眼睑发育的分子调节的理解，并促进我们对上皮细胞迁移和眼睑闭合至关重要的信号网络和分子事件的了解。