MOLECULAR GENETICS OF LENS AND CATARACT DEVELOPMENT

晶状体和白内障发育的分子遗传学

• 批准号: 2162908
• 负责人: RONALD ANTHONY DEPINHO
• 金额: $ 39.02万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-07-01 至 1996-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2162908
• 关键词: RNA; Xenopus; alternatives to animals in research; antibody; antisense nucleic acid; autosomal dominant trait; bromodeoxyuridine; cataract; cell differentiation; congenital eye disorder; crystallins; developmental genetics; epithelium; eye regeneration; fiber cell; gene expression; gene induction /repression; genetic promoter element; genetic techniques; genetically modified animals; immunocytochemistry; in situ hybridization; laboratory mouse; lens; lens proteins; microinjections; molecular genetics; oncoproteins; protooncogene

Cataract disease represents an important health problem that accounts for 22% of all cases of blindness. Over 2 million cataract operations are performed in the US annually. The etiology of cataract disease remains unclear but is clearly multifactorial. Ther heritable predisposition to cataract disease suggest that genetic factors can contribute to the pathogenesis of cataracts. Congenital cataracts whcih manifest as a central (nuclear) opacifications are believed to represent perturbations in normal lens cell differentiation; however, molecular mechanisms governing cataract formation and normal lens differentiation are poorly understood. Myc-family genes (c- N- and L-myc) are believes to play key regulatory roles in normal cell growth and differentiation. Each gene is differentially expressed throughout mammalian development with dramatic changes in the expression of specific myc members coinciding with key developmental transitions in many cell lineages. We ahve demonstrated that as lens fiber cells progress through their developmental program myc-family genes are differentially regulated with respect to developmental stage. For instance, proliferating undifferentiated lens cells express c-myc and L-myc. As these immature cells undergo proliferative arrest and initiate differentiation, both c-myc and L-myc are down-regulated. In contrast, N-myc transcripts are not detectable in immature cells but become abundant at the onset of differentiation. The goal of these studies is to determine the physiological significance of myc in lens differentiation and in the development of cataract disease. To achieve these objectives, we will produce transgenic mice that aberrantly express myc-family genes in the developing lens. With the alphaA-crystallin promoter-enhancer element, we have demonstrated that forced expression of the L-myc gene in differentiating lens cells induces large nuclear congenital cataracts in all cases. Nuclear congenital cataracts may be related to defected lens development and suggests that myc serevs an important role in normal lens cell differentiation. The focus of the proposed studies are (1) to characterize further the structural and molecular features of these alphaA crystallin promoter-driven L-myc transgenic mice, (2) to generate and characterize similar transgenic animals with the c-myc gene, and (3) to utilize dominant interference to abrogate N-myc activity in actively differentiating lens fiber cells, (4) to explore the xpression and function of myc family homologues in the lens of Xenopus laevis.

白内障疾病代表了一个重要的健康问题 在所有失明案件中，有22％。 超过200万白内障手术 每年在美国执行。 白内障疾病的病因 尚不清楚，但显然是多因素的。 可遗传的 白内障疾病的易感性表明遗传因素可以 有助于白内障的发病机理。 先天性白内障 据信作为中央（核）无情的表现代表 正常晶状体细胞分化的扰动；但是，分子 控制白内障形成和正常晶状体分化的机制 知之甚少。 MYC家庭基因（C-N和L-MYC）认为发挥关键调节性 在正常细胞生长和分化中的作用。 每个基因都是 在整个哺乳动物发育中差异表达 特定MYC成员表达的变化与密钥一致 许多细胞谱系中的发育过渡。 我们展示了 随着镜头纤维细胞通过其发展程序的发展 MYC家庭基因受到差异性调节 发展阶段。 例如，增殖未分化的镜头 细胞表达C-MYC和L-MYC。 这些未成熟的细胞经历 C-MYC和L-MYC均增殖和引发分化 被下调。 相反，N-MYC转录本无法检测到 在未成熟的细胞中，但在分化开始时变得丰富。 这些研究的目的是确定生理意义 MYC在晶状体分化和白内障的发展中 疾病。 为了实现这些目标，我们将产生转基因小鼠 在发育中的晶状体中，这种异常表达了Myc家庭基因。 和 alphaa-crystallin启动子增强剂元素，我们已经证明了 L-MYC基因在分化的晶状体细胞中强迫表达 在所有情况下，都会诱导大型核先天性白内障。 核 先天性白内障可能与视镜的发展和 表明MYC SEREV在正常晶状体细胞中起重要作用 分化。 拟议研究的重点是（1） 进一步表征这些结构和分子特征 αA晶状体启动子驱动的L-MYC转基因小鼠（2）生成 并用C-MYC基因表征类似的转基因动物，（3） 利用主要干扰来消除积极的N-MYC活性 区分透镜纤维细胞，（4）探索Xpression和 MYC家族同源物在Xenopus laevis镜头中的功能。