Ubiquitination Lens Proliferation/Differentiation

描述（由申请人提供）：透镜形成需要按时间和空间执行细胞分裂和增殖程序，以及退出细胞周期和分化成透镜纤维。这些过程在大多数细胞类型中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。 这些过程中的畸变经常导致小眼球或白内障。然而，很少有发表的论文，解决无论是透镜细胞周期或其控制的- UPPs。在正在进行的资助期间，我们证明了Ub和Ubc 3（一种Ub连接酶）是增殖和分化所必需的。然而，这些部分对细胞周期的调节发生在G2/M转换，而不是如预测的那样发生在G1/S。 我们现在试图确定是否在转基因动物中通过将突变体Ub的表达定向到上皮细胞和分化中的透镜细胞来在体内观察到相同的对照。我们最近的研究结果提出了两个新的假说：1）Ub和Ubc 3参与的蛋白水解是体内增殖、分化和透镜形成所必需的; 2）Ubc 3-E3相互作用的UPP参与了透镜中G2/M事件的控制。这些总体假设分为4个具体目标，以检验以下假设：活性UPP是体内增殖、分化和透镜形成所需的;泛素化是透镜细胞周期所需的，特别是在G2/M期;透镜Ubc 3与我们将鉴定的E3合作，以控制G2/M转换;以及细胞的控制：G2/M期的细胞周期需要APC调节子在Ubc 3依赖性过程中的泛素化。这些研究将阐述NEI透镜和白内障项目的主要目标：表征透镜细胞分裂和分化的控制及其在继发性白内障形成中的作用。长期目标是延长1）天然透镜的功能，方法是更好地了解控制透镜细胞增殖和分化以及透镜形成的过程，以及2）植入透镜的功能，方法是限制由于过度生长引起的继发性白内障。我们最近的论文表明，这些结果也将导致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，以及我们的新型“试剂”，也将以新的方式用于限制继发性白内障，延长青光眼药物的功能，限制癌症和对抗其他增殖性疾病。我们与优秀的合作者一起努力，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.