BYSTANDER EFFECTS AND X RAY INDUCED GENOMIC INSTABILITY

描述：放射生物学的一个基本范例是， 暴露于电离辐射，这是能量在细胞中的沉积 核是负责其有害的生物效应， DNA是辐射损伤的主要目标。两个迅速扩大的领域 辐射诱导的基因组不稳定性和旁观者效应（BSE） 促使我们重新评估中心法则在这个应用程序中，我们将 研究BSE的作用，即，这些效应发生在 没有受到辐射，但在辐射时是旁观者， 辐射的有害影响。我们建议， 旁观者效应因子（BSEF）被细胞照射刺激， 分泌到培养基中。我们假设这种BSEF是一种蛋白质， 蛋白质复合物BSEF本身可能对观察到的BSE负责， 未照射的细胞和/或可产生活性氧（ROS）， 与这些活性氧共同作用引发疯牛病。反过来，这些ROS可以 刺激BSEF，产生BSEF/ROS/BSEF/ROS循环，从而使来源永久存在 考虑到观察到的有害影响， X射线照射这些假设将在3个具体目标中得到最好的解决： 具体目标1将检验SBEF可以模拟有害物质的假设 X射线照射对未照射细胞的影响。具体目标2将测试 假设我们独特的染色体不稳定克隆的集合可以 产生“不稳定”因子，可诱导细胞遗传学损伤和基因组 非辐射细胞的不稳定性。具体目标3是分离、纯化和 确定导致BSE的因素，以及那些“不稳定”因素 由不稳定的细胞产生。 我们是唯一有资格这样做的。我们手头上有潜在的 BSE，辐射诱导的基因组不稳定性，以及 明确表征的染色体不稳定细胞克隆。We have experience 在分离、纯化和鉴定潜在的BSEF中， 测试候选人的方法。确定BSEF将增强我们的 了解辐射如何产生有害影响， 直接影响辐射暴露的风险评估。

DESCRIPTION:A basic paradigm in radiobiology is that following cellular exposure to ionizing radiation it is the deposition of energy in the cell nucleus that is responsible for its deleterious biological effects, and that DNA is the principal target for radiation damage. Two rapidly expanding fields of research, radiation-induced genomic instability and bystander effects (BSEs) have caused us to reevaluate this central dogma. In this application we will investigate the role of BSEs, i.e., those effects occurring in cells that were not irradiated, but were bystanders at the time of irradiation, in contributing to the deleterious effects of radiation exposure. We propose that some bystander effect factor (BSEF) is stimulated by cellular irradiation and secreted into the culture medium. We hypothesize that this BSEF is a protein to protein complex. The BSEF could itself be responsible for the observed BSEs in non-irradiated cells and/or could generate reactive oxygen species (ROS) and act in conjunction with these ROS to elicit BSEs. In turn these ROS could stimulate BSEF creating cycles of BSEF/ROS/BSEF/ROS, thus perpetuating a source of damage over time to account for the observed detrimental effects of X-irradiation. These hypotheses will be best addressed in 3 specific aims: Specific aim 1 will test the hypothesis that the SBEF can mimic the deleterious effects of X-ray exposure in non-irradiated cells. Specific aim 2 will test the hypothesis that our unique collection of chromosomally unstable cloned can produce "instability" factor(s) that can induce cytogenetic damage and genomic instability in non-irradiated cells. Specific aim 3 is to isolate, purify, and identify the factor(s) responsible for the BSE, and those "instability" factors produced by unstable cells. We are uniquely qualified to do this. We have in hand the assays for potential BSEs, radiation-induced genomic instability, and a collection of well-characterized chromosomally unstable clones of cells. We have experience in isolating, purifying, and identifying potential BSEF(s) and have the methodology to test candidates. Identifying the BSEF would enhance our understanding of how radiation exerts its deleterious effects and could directly impact risk estimation for radiation exposure.