ROLE AND REGULATION OF CDK4 IN THE NORMAL LENS

阐明了控制细胞生长的分子机制， 对我们理解正常发育和癌症至关重要。的目标 本研究的目的是探索细胞周期的主要调控机制， 检查点，G1/S转换，在发育小鼠的背景下 透镜。我们的主要重点将是对G1细胞周期蛋白依赖的调控， 激酶（cdk），cdk 4及其与视网膜母细胞瘤的功能关系 (Rb)蛋白cdk 4复合体已经占据了细胞周期的中心阶段 由于其在增殖反应中的重要性， 细胞对生长因子及其相关蛋白质的参与 在癌症发病机制中。cdk 4复合物的活性在很大程度上受到调节。 通过与阳性（细胞周期蛋白D）和阴性（细胞周期蛋白D）的直接相互作用 （cdk 4的抑制剂，例如p15/INK 4和p16 INK 4）调节蛋白。由于 在过去6年的基础上，我的实验室现在是独一无二的。 能够以全面的方式处理cdk 4的功能， 其相关的调节蛋白在正常哺乳动物发育中的作用。这 机会来自于（i）将透镜建立为理想系统 用于检查体内生长控制（EMBO J，1995），并证明 Rb是cdk 4的底物，在透镜细胞中起着核心和重要的作用 生长控制（自然，1994年），（ii）功能的表征 几种细胞中p16 INK 4、cdk 4、Myc和Rb蛋白相互关系 培养系统（Science，1995），（iii）产生4种不同的转基因 小鼠系（各种细胞周期蛋白D和cdk 4构建体）和种系空 p16 INK 4基因的突变，（iv）癌症易感转基因的可用性， 我们和其他人已经生成的小鼠模型，最重要的是，（v） 在使用小鼠作为实验系统方面的丰富经验， 基因功能分析。这一完整补充的特征 功能获得和功能丧失小鼠模型将使我们能够 了解细胞周期蛋白D、cdk 4和p15 INK 4、p16 INK 4基因在 在体内正常组织中和在体内正常组织中G1/S转换的调节， 癌症的起源关于癌症研究，我们将检查和 比较每种小鼠模型中肿瘤的发生和分布 单独地，彼此结合，或与癌症结合- 易感小鼠（如p53-/-或我们的一些Myc转基因小鼠）。最后 p16 INK 4与家族性黑色素瘤的联系将促使对 无p16 INK小鼠的UV暴露是否加速皮肤的发育 癌的

Elucidation of the molecular mechanisms governing cellular growth is central to our understanding of normal development and cancer. The goal of this proposal is to explore the regulation of the principal cell cycle checkpoint, the G1/S transition, in the context of the developing mouse lens. Our main focus will be on the regulation of a G1 cyclin-dependent kinase (cdk), cdk4, and its functional relationship to the retinoblastoma (Rb) protein. The cdk4 complex has captured center stage in the cell cycle field because of its documented importance in the proliferative response of cells to growth factors and of the involvement of its associated proteins in cancer pathogenesis. Activity of the cdk4 complex is regulated in large part through direct interactions with positive (cyclin D) and negative (inhibitors of cdk4, e.g. p15/INK4 and p16INK4) modulatory proteins. Owing to a foundation laid over the past 6 years, my laboratory is now uniquely positioned to address in a comprehensive manner the function of cdk4 and its associated regulatory proteins in normal mammalian development. This opportunity arises from (i) establishment of the lens as an ideal system for examining growth control in vivo (EMBO J, 1995) and demonstration that Rb, the substrate of cdk4, plays a central and essential role in lens cell growth control (Nature, 1994), (ii) characterization of the functional interrelationships among p16INK4, cdk4, Myc and Rb proteins in several cell culture systems (Science, 1995), (iii) generation of 4 different transgenic mouse lines (various cyclin D and cdk4 constructs) and a germline null mutation of the pl6INK4 gene, (iv) availability of cancer-prone transgenic mouse models that we and others have generated, and most importantly, (v) extensive experience in employing the mouse as an experimental system for the analysis of gene function. Characterization of this full complement of gain-of function and loss-of-function mouse models will allow us to understand the function of cyclin D, cdk4, and p15INK4, p16INK4 genes in the regulation of the G1/S transition in normal tissues in vivo and in the genesis of cancer. With respect to the cancer studies, we will examine and compare the onset and distribution of tumors arising in each mouse model separately, in combination with each other, or in conjunction with cancer- prone mice (such as p53-/- or some of our Myc transgenics). Finally, the connection of p16INK4 to familial melanoma will prompt an assessment of whether UV exposure of null p16INK mice accelerates the development of skin cancers.