ROLE OF RAD9 IN BYSTANDER EFFECTS

RAD9 在旁观者效应中的作用

• 批准号: 7992111
• 负责人: HOWARD B. LIEBERMAN
• 金额: $ 75.88万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7992111
• 关键词: Address; Apoptosis; Binding; Biological; Biological Assay; Bystander Effect; Cell Cycle; Cell Cycle Checkpoint; Cell Nucleus; Cell physiology; Cells; Collaborations; Communication; Connexins; Cytoplasm; DNA Repair; DNA Repair Gene; Female; Gene Expression; Gene Targeting; Genes; Genomic Instability; Genotype; Goals; Growth; Health; Hela Cells; Human; In Vitro; Incidence; Ionizing radiation; Lead; Lung; Mammary gland; Mediating; Molecular; Mus; Mutagenesis; Mutation; Nuclear; Pathway interactions; Play; Population; Process; Production; Promoter Regions; Protein Binding Domain; Proteins; RNA; Radiation; Radiation therapy; Regulation; Research Personnel; Reverse Transcriptase Polymerase Chain Reaction; Risk; Risk Assessment; Role; Scanning; Signal Transduction; Small Interfering RNA; Testing; Thinking; Time; Tissues; Transactivation; Transgenic Organisms; Up-Regulation; Work; base; connexin 32; embryonic stem cell; gene induction; improved; in vivo; irradiation; knock-down; micronucleus; mutant; null mutation; overexpression; protein function; rad9 protein; radiation effect; radiation resistance; response

The overall cellular response to ionizing radiation exposure is not limited to cells directly irradiated, but includes neighboring "bystanders". Essentially every endpoint used routinely to test for changes in cells direcfiy exposed to radiation, such as mutation, apoptosis, micronuclei formation or cell cycle checkpoints, has been studied in bystanders. This phenomenon has caused a paradigm shift in thinking about biological effects and associated health risks of radiafion exposure; the impacted cell population is larger than once believed. The mechanism regulating bystander effects is not well understood. However, certain gap junction proteins, i.e., Connexin 32, and proteins like Cox-2 control the overall process, whereas p21 just regulates the radiation-induced Gl to S checkpoint. We have shown that Rad9 regulates the bystander response to radiation, since Rad9 null enhances bystander apoptosis and micronuclei formation. Rad9 protein, which controls cell cycle checkpoints, DNA repair, apoptosis and transactivation of downstream target genes in directly irradiated cells, likely impacts on the bystander response via more than one pathway. In collaboration with investigators in Projects 2 and 3, we show that Rad9 is essential for bystander induction of Cox-2 and p21 (Project 2), and production of Connexin 32 in HeLa cells, which are normally devoid of the protein, increases bystander radiation resistance and levels of Rad9 as well as TCTP (Project 3), which both function in the bystander process. We also show that TCTP and Rad9 physically interact (Project 3). Our overarching hypothesis is that Rad9 plays an important role in radiation-induced bystander effects via mechanisms involving at least Cox-2, p2I, Connexin 32 and TCTP. Specific aims to address this hypothesis are: I. Determine the activity of Rad9 in nuclear versus cytoplasmic irradiation-induced bystander effects; 2. Analyze Rad9 functional domains and protein-protein interactions for roles in the bystander process; 3. Establish the significance of Rad9-dependent bystander induction of Cox-2, p21 and other genes for bystander regulation; 4. Determine if Rad9 is critical for bystander mutagenesis; and 5. Define the significance of junctional communication on the regulation and funcfion of Rad9. These studies will reveal mechanisms by which Rad9 regulates radiation-induced bystander effects, and will impact on understanding the biological response to radiation exposure, with implications for improving radiotherapy and better defining health risk.

对电离辐射暴露暴露的总体细胞反应不限于直接辐照的细胞，而是 包括相邻的“旁观者”。本质上，每个端点通常用于测试细胞的变化 暴露于辐射的直接表面，例如突变，凋亡，微核形成或细胞周期检查点， 已经在旁观者中进行了研究。这种现象在思考生物学方面引起了范式的转变 远期暴露的影响和相关的健康风险；受影响的细胞种群比一次大 相信。调节旁观者效应的机制尚不清楚。但是，某些间隙连接点 蛋白质，即连接蛋白32，而蛋白质像COX-2这样的蛋白质控制整体过程，而P21只是调节 辐射诱导的GL到S检查点。我们已经表明，rad9调节旁观者对 辐射，因为rad9 null增强了旁观者的凋亡和微核形成。 rad9蛋白，它 控制细胞周期检查点，DNA修复，凋亡和下游靶基因的反式激活 直接辐照的细胞可能会通过多个途径影响旁观者的反应。合作 在项目2和3的研究人员中，我们表明RAD9对于旁观者的COX-2和 p21（项目2），以及在通常没有蛋白质的HeLa细胞中的连接蛋白32的产生 增加旁观者的辐射阻力和RAD9的水平以及TCTP（项目3），这两者都起作用 在旁观者过程中。我们还表明TCTP和RAD9物理相互作用（项目3）。我们的总体 假设是Rad9通过机制在辐射引起的旁观者效应中起重要作用 至少涉及COX-2，P2I，CONNEXIN 32和TCTP。解决这一假设的具体目的是：I。 确定RAD9在核与细胞质辐照引起的旁观者效应中的活性； 2。 分析RAD9功能结构域和蛋白质 - 蛋白质相互作用在旁观者过程中的作用； 3。 确定cox-2，p21和其他基因对Rad9依赖性旁观者诱导者对旁观者的重要性 规定; 4。确定rad9对于旁观者诱变至关重要；和5。定义的意义 RAD9的调节和功能的连接通信。这些研究将通过 RAD9调节辐射引起的旁观者效应，并将影响了解生物学 对辐射暴露的反应，对改善放射疗法和更好地定义健康风险的影响。