ROLE AND REGULATION OF CDK4 IN THE NORMAL LENS

阐明控制细胞生长的分子机制是 对于我们对正常发育和癌症的理解至关重要。的目标是 这项建议是为了探索对主细胞周期的调节 检查点，G1/S的过渡，在开发中的鼠标的上下文中 镜头。我们的主要关注点将放在对依赖于细胞周期蛋白G1的调控上 CDK、CDK4及其与视网膜母细胞瘤的功能关系 (Rb)蛋白质。CDK4复合体占据了细胞周期的中心阶段 领域，因为它在增殖反应中的重要文献记载的重要性 细胞对生长因子及其相关蛋白的参与 在癌症发病机制中的作用。CDK4复合体的活性在很大程度上受到调节 部分通过与正性(细胞周期蛋白D)和负性的直接相互作用 (CDK4的抑制剂，例如p15/INK4和p16INK4)调节蛋白。欠款 在过去的6年里奠定了基础，我的实验室现在是独一无二的 定位为全面解决CDK4的功能和 它在哺乳动物正常发育过程中的相关调节蛋白。这 机会来自(一)将镜片建立为理想的系统 用于检查体内的生长控制(EMBO J，1995)并证明 Rb是CDK4的底物，在晶状体细胞中起着核心和重要的作用 生长控制(自然，1994)，(Ii)功能性 几种细胞中p16INK4、CDK4、Myc和Rb蛋白的相互关系 培养系统(科学，1995)，(Iii)4种不同转基因的产生 小鼠品系(各种细胞周期蛋白D和CDK4结构)和生殖系Null Pl6INK4基因的突变，(Iv)易癌转基因的可用性 我们和其他人创造的小鼠模型，最重要的是，(V) 使用鼠标作为实验系统的丰富经验 基因功能分析。对这一完整补充性的描述 功能增强和功能丧失的鼠标模型将使我们能够 了解细胞周期蛋白D、CDK4和p15INK4、p16INK4基因在 G1期/S期细胞周期在正常组织中的调节 癌症的起源。关于癌症研究，我们将审查和 比较每种小鼠模型中肿瘤的发生和分布 单独地，相互结合，或与癌症结合- 容易感染的小鼠(例如P53-/-或我们的一些Myc转基因基因)。最后， P16INK4与家族性黑色素瘤的联系将促使对 P16INK裸鼠紫外线照射是否加速皮肤发育 癌症。

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.