Ubiquitination Lens Proliferation/Differentiation

描述（由申请人提供）：晶状体的形成需要一个按时间和空间顺序执行的细胞分裂和增殖程序，以及细胞周期的退出和晶状体纤维的分化。在大多数细胞类型中，这些过程是通过泛素蛋白酶体途径（UPPs）及时降解细胞周期调节剂来控制的。这些过程中的畸变经常导致小眼或白内障。然而，很少有已发表的论文涉及晶状体细胞周期或其由- UPPs控制。在正在进行的资助中，我们证明了Ub和Ubc3（一个Ub连接酶）是增殖和分化所必需的。然而，这些片段对细胞周期的调控发生在G2/M过渡期，而不是像预测的那样发生在G1/S过渡期。我们现在试图通过在转基因动物中将突变的Ub直接表达到上皮细胞和分化的晶状体细胞来确定是否在体内观察到相同的控制。我们最近的数据产生了两个新的假设：1)涉及Ub和Ubc3的蛋白质水解是体内增殖、分化和晶状体形成所必需的；2)涉及未描述的Ubc3-E3相互作用的UPP参与透镜中G2/M事件的控制。这些总体假设分为4个具体目标，以验证以下假设：活性UPP是体内增殖、分化和晶状体形成所必需的；晶状体细胞周期需要泛素化，特别是G2/M；镜头Ubc3与E3配合，我们将识别，以控制G2/M过渡；G2/M时细胞周期的控制需要APC调节因子在ubc3依赖性过程中泛素化。这些研究将解决NEI晶状体和白内障项目的一个主要目标：表征晶状体细胞分裂和分化的控制，以及它们在继发性白内障形成中的作用。长期目标是通过更好地了解晶状体细胞增殖和分化以及晶状体形成的控制过程来延长天然晶状体的功能，以及通过限制过度生长引起的继发性白内障来延长人工晶状体的功能。我们最近的论文表明，这些结果也将有助于更好地理解角膜伤口愈合和视网膜对压力的反应。这些信息，以及我们的新“试剂”，也将以新的方式用于限制继发性白内障，延长青光眼药物的作用，限制癌症和对抗其他增生性疾病。我们有优秀的合作者，他们每个人都是他所在领域的领导者。

DESCRIPTION (provided by applicant): Lens formation requires a chronologically and spatially executed program of cell division and proliferation, as well as exit from the cell cycle and differentiation into lens fibers. These processes are controlled in most cell types by the timely degradation of cell cycle regulators by Ubiquitin Proteasome Pathways (UPPs). Aberrations, in these processes frequently result in microphthalmia or cataract. Yet there are few published papers that address either the lens cell cycle or its control by- UPPs. During the ongoing grant, we demonstrated that Ub and Ubc3 (a Ub ligase) are required for proliferation and differentiation. However, regulation of the cell cycle by-these moieties occurs at the G2/M transition and not, as predicted, at G1/S. We now seek to determine if the same controls are observed in vivo by directing expression of mutant Ub to the epithelial and differentiating lens cells in transgenic animals. Our recent data beget two new overall hypotheses: 1) proteolysis involving Ub and Ubc3 is required for proliferation, differentiation, and lens formation in vivo; 2) a UPP which involves an undescribed Ubc3-E3 interaction is involved in control of G2/M events in lens. These overall hypotheses are separated into 4 specific aims, to test the hypotheses that: an active UPP is required for proliferation, differentiation and lens formation in vivo; ubiquitination is required for the lens cell cycle, particularly in G2/M; lens Ubc3 cooperates with an E3, which we will identify, to control the G2/M transition; and control of the cell: cycle at G2/M requires ubiquitination of the APC regulators in a Ubc3-dependent process. These studies will address a major objective of the NEI lens and cataract program: to characterize controls of lens cell division and differentiation, and their roles in formation of secondary cataract. The long-term objective is to prolong function of 1) the natural lens by gaining a better understanding of processes involved in control of lens cell proliferation and differentiation, as well as in lens formation, and 2) implanted lenses by limiting secondary cataract due to overgrowth. Our recent papers show that these results will also lead to a better understanding of corneal wound healing and retina responses to stress. This information, and our novel "reagents", will also find use in new ways to limit secondary cataract, prolong function of glaucoma medication, limit cancer and in fighting other proliferative maladies. We are joined in this effort by excellent collaborators, each of whom is a leader in his field.