CYTOGENETICS--ALPHA PARTICLE INDUCED CHROMOSOMAL CHANGES

产品说明：（申请人的描述）该计划项目的总体研究目标是了解辐射诱导损伤的识别，处理和后果的机制基础，特别强调氡子体α粒子及其对人类健康的影响。核DNA的变化显著影响人类健康，与细胞死亡、突变和致癌变化有明确的关系。然而，在非核目标中引起的应力对长期有害影响的潜在贡献方面存在不确定性。很明显，细胞膜、细胞质和细胞核之间的分子相互作用有助于损伤识别、信号传导和反应途径。通过使用微束，可以有效地了解细胞成分在辐射反应中的作用。在这个项目中，我们将使用定义的影响（低至1）或100千电子伏/微米α粒子照射细胞核，细胞质或已知的细胞在人口。非命中细胞（旁观者）可能受到活性氧物质的应激和/或受到诱导的移动的细胞因子的影响。来自敲除小鼠、野生型、p53-和atm-的小鼠胚胎成纤维细胞将作为单个和成对群体进行辐照。将在命中与非命中单元格中单独评估应答。我们将提出以下问题：粒子间距是否影响基于原子核的反应？细胞质照射是否会引发生物学反应？细胞特异性照射是否在基因型依赖的基础上启动非命中细胞的反应？我们将检查微核的发生率;细胞凋亡、细胞生长和发育;细胞周期延迟;通过蛋白质表达和定位的基因表达，以及通过RT-PCR的mRNA。与该项目的其他项目一致，终点和精确的部位特异性微束辐照的组合以解决确定性问题将建立机制参数，并将定义低剂量下的α粒子反应性，重点是旁观者效应的贡献。

DESCRIPTION: (Applicant's Description) The overall research objectives of this program project are directed toward understanding the mechanistic bases for the recognition, processing and consequences of radiation induced lesions, with a particular emphasis on radon progeny alpha particles and their impact on human health. Nuclear DNA changes significantly impact human health with clear relationships to cell death, mutation and oncogenic changes. There is uncertainty however as to the potential contributions of stresses induced in non-nuclear targets to long term deleterious effects. It is clear that molecular interplay between membrane, cytoplasm and nucleus contributes to damage recognition, signaling and response pathways. An understanding of the role of cellular components in radiation responses can efficiently be obtained by use of a microbeam. In this project we will used defined influences (down to 1) or 100 keV/um alpha-particles to irradiate cell nucleus, cytoplasm or known cells in a population. Non-hit cells (bystanders) may be stressed by reactive oxygen species and/or affected by induced mobile cytokines. Mouse embryo fibroblasts derived from knockout mice, wild-type, p53-, and atm- will be irradiated both as single and as pair wise populations. Responses will be separately assessed in hit versus non-hit cells. We will ask the questions: Does particle spacing influence nucleus based responses? Does cytoplasmic irradiation initiate a biological response? Does cell specific irradiation initiate responses in non-hit cells on a genotype dependent basis? We will examine incidence of micronuclei; apoptosis, cell growth and development; cell cycle delay; and gene expression both by protein expression and localization, and mRNA by RT-PCR. In concert with the other projects of this program project, the combination of endpoints and precise site specific microbeam irradiation to address definitive question will establish mechanistic parameters and will define alpha-particle responsiveness at low doses with emphasis on the contribution of the bystander effect.