CELL CYCLE AND CELL DEATH STUDIES IN THE OCULAR LENS

人工晶状体为研究细胞周期调控提供了理想的系统。 在顶端分化过程中。晶状体由两种细胞类型组成： 具有细胞增殖能力的上皮细胞，以及 纤维细胞，这是有丝分裂后。我猜想 上皮细胞分化为纤维细胞会导致 调节细胞周期的基因活性的变化。在……里面 为了帮助验证这一假说，αA-晶体蛋白启动子将是 用于指导转基因中晶状体特异性基因表达的改变 老鼠。转基因和非转基因小鼠将被用于研究两个 可能对细胞周期至关重要的基因的一般类别 分化调控：肿瘤抑制因子和细胞周期蛋白依赖性 激活剂。本次拨款申请的具体目的是：L)评估 视网膜母细胞瘤(RB)蛋白在细胞周期调控和调控中的作用 晶状体纤维细胞的终末分化；2)评估P53的作用 在SV4O大T抗原诱导晶状体肿瘤中的作用 伴随纤维细胞的细胞周期蛋白依赖性蛋白激酶的变化 分化；4)表征Rb诱导的细胞死亡 纤维细胞失活；5)遗传逆转晶状体 全长T抗原诱导的肿瘤发生。我们的预赛 实验表明，与Rb结合的病毒蛋白的表达 和/或P53可诱导晶状体细胞肿瘤发生或程序性细胞死亡。 因此，晶状体细胞的细胞周期可以用迷人的方式改变 以及意想不到的后果。拟议的研究应提供见解 体内的细胞周期调节，不仅对晶状体，而且对其他 正在经历末端分化或肿瘤性转化的细胞。

The ocular lens provides an ideal system to study cell cycle regulation during terminal differentiation. The lens is composed of two cell types: the epithelial cells, which are capable of cellular proliferation, and the fiber cells, which are post-mitotic. I hypothesize that the differentiation of epithelial cells into fiber cells will cause alterations in activity of the genes that regulate the cell cycle. In order to help test this hypothesis, the alphaA-crystallin promoter will be used to direct lens-specific alterations in gene expression in transgenic mice. Transgenic and non-transgenic mice will be used to study two general classes of genes that are likely to be critical for cell cycle control during differentiation: tumor suppressors and cyclin-dependent kinases. The Specific Aims of this grant application are: l) to assess the role of the retinoblastoma (rb) protein in cell cycle control and terminal differentiation of lens fiber cells; 2) to assess the role of p53 in the induction of lens tumors by SV4O large T antigen; 3) to assay for changes in cyclin dependent kinases that accompany fiber cell differentiation; 4) to characterize the cell death that is induced by rb inactivation in fiber cells; and 5) to genetically reverse lens tumorigenesis induced by full-length T antigen. Our preliminary experiments have shown that expression of viral proteins that bind to rb and/or p53 can induce lens cell tumorigenesis or programmed cell death. Therefore, the cell cycle can be altered in lens cells with fascinating and unexpected consequences. The proposed studies should provide insights into cell cycle regulation in vivo, not only for the lens, but for other cells undergoing terminal differentiation or neoplastic transformation.