Growth-regulatory targets of Drosophila Cyclin D/Cdk4

描述（由申请人提供）：Ink 4/细胞周期蛋白D1/视网膜母细胞瘤通路的至少一种组分的失调是大多数人类癌症的共同特征，但这些基因促进肿瘤发生的机制知之甚少。在使用果蝇的研究中，我们发现细胞周期蛋白D/Cdk 4复合物，除了作为细胞周期进程的启动子被广泛认可的功能外，还调节细胞质量（生长）的增加速率。CycD/Cdk 4通过未知的靶点来实现这一点，与研究充分的pRb/E2 F途径中的靶点不同。我们正在使用果蝇遗传学来识别和表征这些新的生长调节靶点，我们认为这对于理解正常和肿瘤发育过程中CycD/Cdk 4的功能可能很重要。本项目的具体目标包括：1）利用已证实的、全基因组范围的突变筛选来鉴定和表征CycD/Cdk 4的生长调节靶点，所述突变主要抑制由异位CycD/Cdk 4引起的眼过度生长; 2）通过基因表达谱鉴定CycD/Cdk 4靶点; 3）开发用于表征推定靶点的果蝇CycD/Cdk 4激酶测定; 4）表征Hph/Hif-1/VHL和JAK/STAT途径作为CycD/Cdk 4驱动的生长的介体;和5）测试以确定CycD/Cdk 4是否通过调节营养输入、蛋白质合成、蛋白质降解或线粒体功能来影响细胞生长。该项目旨在阐明CycD/Cdk 4如何改变细胞生理学以促进生长，并应有助于解释细胞生长和细胞分裂如何耦合的分子范式。它还应该允许识别人类中新的细胞周期蛋白D和Ink 4靶点，从而有助于揭示我们自己的细胞在正常和肿瘤发育过程中的生长是如何控制的。一些被鉴定的基因可能是癌症诊断或抗癌化疗的有用靶点。

DESCRIPTION (provided by applicant): Deregulation of at least one component of the Ink4/Cyclin D1/retinoblastoma pathway is a common feature of most of human cancers, but the mechanism by which these genes contribute to tumorigenesis is poorly understood. In studies using Drosophila we discovered that Cyclin D/Cdk4 complexes, in addition to their widely appreciated function as promoters of cell cycle progression, also regulate rates of increase in cell mass (growth). CycD/Cdk4 does this via unknown targets, distinct from those in the well-studied pRb/E2F pathway. We are using Drosophila genetics to identify and characterize these novel growth-regulatory targets, which we believe may be important for understanding CycD/Cdk4 function during normal and neoplastic development. Specific aims of this project comprise: 1) Identification and characterization of growth regulatory targets of CycD/Cdk4 using proven, genome-wide screens for mutations that dominantly suppress overgrowth of the eye caused by ectopic CycD/Cdk4; 2) Identification of CycD/Cdk4 targets by gene expression profiling; 3) development of a Drosophila CycD/Cdk4 kinase assay for characterizing putative targets; 4) Characterizing the Hph/Hif-1/VHL and JAK/STAT pathways as mediators of CycD/Cdk4-driven growth; and 5) Tests to determine whether CycD/Cdk4 effects cellular growth by modulating nutrient import, protein synthesis, protein degradation, or mitochondrial function. This project aims to elucidate how CycD/Cdk4 alters cell physiology to promote growth, and should contribute to molecular paradigms explaining how cell growth and cell division are coupled. It should also allow identification of novel Cyclin D and Ink4 targets in humans, and thus help to reveal how growth of our own cells is controlled during normal and neoplastic development. Some of the identified genes could be useful targets for cancer diagnosis or anti-cancer chemotherapeutics.