GENE EXPRESSION IN THE NORMAL AND CATARACTOUS LENS

眼睛的透明度和人类透镜的生长取决于 透镜上皮细胞向纤维细胞的适当分化。 我们首次开发了体外细胞培养 来自胎儿人透镜上皮细胞的系统， 显示上皮细胞特异性多肽的合成未减弱， α B-晶状体蛋白（α B），但也是一种渐进性表达， 纤维细胞特异性蛋白BetaBp-晶状体蛋白（BetaBp）指示 维持这些细胞分化的承诺 体外 非常重要的是，我们已经展示了额外的晶状体 alphaB的存在表明可能的调节，而不是 而不是这种蛋白质的结构作用。 本研究将 研究人类中alphaB合成的调节 透镜上皮细胞，以了解其在分化中的作用， 去分化，和/或在功能维持中， 正常和患病状态下的透镜上皮。 我们还将 研究BetaBp激活的分子机制 基因，在这些细胞从初级向次级转变时， 文化，为研究提供了一个非常相关的范式， 纤维细胞特异性基因的激活。 这次调查 将需要通过测序进行分离和物理表征 人α B和β Bp晶体蛋白基因的顺式 两个基因的调控元件在两侧5- 10 kb之间 以及细胞类型的鉴定和表征 或分化特异性反式作用蛋白因子 在维持β B合成和激活 BetaBp的合成。 因为去分化和丧失 已知上皮细胞的组织能力是 在诸如前和后 囊下混浊，本研究将试图调查 α B的作用，例如在维持上皮表型中的作用， 从而在上皮细胞分化成纤维细胞时， 非白内障透镜的先天发育过程。

Ocular transparency and growth of the human lens are dependent on the proper differentiation of lens epithelium into fiber cells. We have for the first time developed an in vitro cell culture system from the fetal human lens epithelial cells which not only shows unabated synthesis of epithelial cell specific polypeptide, alphaB-crystallin(alphaB) but also a progressive expression of fiber cell specific protein BetaBp-crystallin (BetaBp) indicating maintenance of the commitment within these cells to differentiate in vitro. Very importantly, we have shown extra-lenticular presence of alphaB which has suggested a possible regulatory rather than a structural role for this protein. The present study will investigate the regulation of the synthesis of alphaB in the human lens epithelial cells to understand its role in differentiation and de-differentiation, and/or in the functional maintenance of the lens epithelium in normal and diseased states. We will also investigate the molecular mechanistics of the activation of BetaBp gene, upon transition of these cells from a primary to a secondary culture which presents a very relevant paradigm for the study of the activation of a fiber cell specific gene. This investigation will entail isolation and physical characterization by sequencing of human alphaB and BetaBp crystallin genes; delineation of the cis regulatory elements in the two genes within 5-10kb on either side of each gene and identification and characterization of cell-type or differentiation-specific trans acting protein factors involved in the maintenance of the synthesis of BetaB and activation of the synthesis of BetaBp. Because de-differentiation and loss of the organizational competence of the epithelial cells is known to be compromised in pathologies such as anterior and posterior subcapsular opacities, this study will attempt to investigate the role of alphaB e.g. in maintenance of the epithelial phenotype and thereby in the differentiation of epithelium into fiber cells, a developmental process so very innate to a non cataractous lens.