LUMICAN AND EYE DEVELOPMENT AND FUNCTIONS

Lumican是角膜基质的主要蛋白多糖组分， 被认为在角膜透明度中起着关键作用。 在角膜中， 通过高度有序的排列， 直径均匀细的胶原纤维。 Lumican抑制 胶原纤维在体外的横向生长，并可能具有类似的 对角膜中胶原纤维形成的影响。 硫酸角质素 Lumican的糖胺聚糖侧链保留水分， 保持透明所需的纤维间距。 的 Lumican对胶原蛋白影响的分子相互作用 对原纤维的了解很少。 PI的初步结果还表明， Lumican在发育中的角膜基质中很早就表达， 暗示这种蛋白聚糖在角膜发育中的潜在作用。 本研究的目的是阐明Lumican在角膜中的作用。 第一个目标是确定Lumican的分子机制 与胶原蛋白的相互作用，并深入了解这一重要方面 在角膜中的作用。 这一目标将决定 结合动力学和鉴定Lumican核心蛋白上的位点， 在胶原蛋白结合和抑制原纤维的横向生长方面具有活性。 第二个目的是确定Lumican是否抑制细胞粘附到 胶原蛋白或纤连蛋白底物，因此，可能调节 角膜发育过程中的间充质细胞粘附/迁移 基质。 第三个目标是通过靶向的免疫调节来产生Lumican缺陷小鼠。 删除Lumican基因并确定其对发育的影响 以及角膜的结构和功能。 本研究中提出的体外实验将确定 Lumican核心蛋白的功能重要区域， Lumican的体内定点诱变研究。 靶向的基因 本研究中提出的删除Lumican的建议将首次， 解决它在体内的作用和它的缺乏对 角膜 通常，长期目标是开发小鼠模型 对于角膜营养不良，另一种结缔组织疾病， 蛋白聚糖-胶原基质。

Lumican is a major proteoglycan component of the corneal stroma and believed to play a pivotal role in corneal transparency. In the cornea, transparency is combined with tensile strength by a highly ordered array of collagen fibrils of uniformly thin diameter. Lumican inhibits lateral growth of collagen fibrils in vitro and may have a similar effect on collagen fibril formation in the cornea. The keratan sulfate glycosaminoglycan side chains of lumican retain water and help to maintain interfibrillar spacing necessary for transparency. The molecular interactions underlying lumican's influence on collagen fibrils are poorly understood. The PI preliminary results also indicate that lumican is expressed very early in the developing corneal stroma, implying a potential role for this proteoglycan in corneal development. The purpose of this study is to elucidate lumican's role in the cornea. The first aim is to define the molecular mechanism underlying lumican's interactions with collagen and gain insight into this important aspect of lumican's function in the cornea. this aim will determine the binding kinetics and identify sites on the lumican core protein that are active in collagen-binding and inhibiting lateral growth of fibrils. The second aim is to determine if lumican inhibits cell adhesion to collagen or fibronectin substrates, and thus, likely to regulate mesenchymal cell adhesion/migration during development of the corneal stroma. The third aim is to generate lumican-deficient mice by targeted deletion of the gene for lumican and determine its effect on development of the eye and structure and functions of the cornea. The in vitro experiments proposed in this study will identify functionally important regions of the lumican core protein for future site-directed mutagenesis studies of lumican in vivo. The gene targeted deletion of lumican proposed in this study will, for the first time, address its role in vivo and the overall effect of its absence on the cornea. Generally, the long term objectives are to develop mouse models for corneal dystrophies another connective tissue disorders with altered proteoglycan-collagen matrices.