An Assay to Identify and Classify Epimutagens

描述(申请人提供)：这项提案旨在开发一种方法来筛选扰乱哺乳动物细胞表观遗传过程的化学试剂。表观遗传学研究的是DNA功能的可遗传变化，不涉及DNA序列的改变。在哺乳动物和其他多细胞生物中，大多数基因组通过表观遗传机制保持在沉默的转录状态。这种沉默状态的破坏可能会产生严重的影响，包括发育异常和癌症。众所周知，一些化学物质可以破坏表观遗传沉默，但我们还没有全面了解可以起到“表观诱变剂”作用的环境因子。我们假设有许多化学的表观诱变剂。为了促进这些药物的发现和研究，我们建议开发一种基于哺乳动物细胞的系统，该系统可以在哺乳动物细胞中筛选表观诱变活性。我们将采用一个我们广泛使用的系统来研究转基因在培养细胞中的表观遗传沉默。通过选择对已知表观诱变剂破坏表观遗传沉默敏感的细胞克隆，我们将获得一组细胞系，这些细胞系可以用类似于Ames突变试验的方式来筛选表观诱变活性。公共卫生相关性：人类发展和疾病普遍受到表观遗传过程的影响。可能有许多环境因子能够破坏表观遗传沉默并造成健康影响，但我们缺乏容易识别它们的手段。我们建议开发一种系统，允许对大量化学物质进行表观遗传效应筛选。公共卫生相关性：为了保护人类免受有害环境化学品的伤害，需要存在从人们接触的数百万饮食和工业化学品中识别此类化合物的手段。自20世纪70年代以来，对突变化合物的测试--那些会导致DNA序列错误并因此具有致癌作用的化合物--就已经存在了。然而，另一类潜在的致癌物质，即表观致突变化合物，目前无法检测到；对这类化合物的研究和监管并不是环境健康监测的常规部分。我们建议开发检测和测量表观诱变剂的工具，最终使环境保护措施到位。

DESCRIPTION (provided by applicant): This proposal aims to develop a method to screen for chemical agents that disrupt epigenetic processes in mammalian cells. Epigenetics deals with heritable changes to the function of DNA that does not involve altered DNA sequence. In mammals and other multicellular organisms, most of the genome is kept in a silent transcriptional state by epigenetic mechanisms. Disruption of this silent state can have drastic effects, including developmental anomalies and cancer. Some chemicals are known to disrupt epigenetic silencing, but we have no comprehensive picture of the environmental agents that can act as "epimutagens". We hypothesize that there are many chemical epimutagens. In order to facilitate the discovery and study of these agents, we propose to develop a mammalian cell-based system that can screen for epimutagenic activity in mammalian cells. We will adapt a system that we have used extensively to study epigenetic silencing of transgenes in cultured cells. By selecting for cell clones that are sensitive to the disruption of epigenetic silencing by known epimutagens, we will derive a panel of cell lines that can be used to screen for epimutagenic activity in a manner analogous to the Ames test for mutagenicity. PUBLIC HEALTH RELEVANCE: Human development and disease are pervasively affected by epigenetic processes. There may be many environmental agents that are capable of disrupting epigenetic silencing and causing health effects, but we lack the means to readily identify them. We propose to develop a system that will permit screening of large numbers of chemicals for epigenetic effects. PUBLIC HEALTH RELEVANCE: The protection of humans from harmful environmental chemicals requires the existence of means to identify such compounds from among the millions of dietary and industrial chemicals to which people are exposed. Tests for mutagenic compounds-those that cause errors in the sequence of DNA and are therefore carcinogenic-have existed since the 1970s. Another class of potential carcinogen, however, the class of epimutagenic compounds, is currently undetectable; research into and regulation of such compounds is not a routine part of environmental health monitoring. We propose to develop tools for the detection and measurement of epimutagens, ultimately enabling environmental protections to be put in place.