ARYLAMINE ACETYLTRANSFERASES AND DEVELOPMENTAL TOXICITY

芳胺乙酰转移酶和发育毒性

• 批准号: 6350832
• 负责人: Charlene A McQueen
• 金额: $ 17.9万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-01 至 2003-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6350832
• 关键词: acetylation; acyltransferase; developmental genetics; embryo /fetus toxicology; female; gene expression; genetic polymorphism; genotype; laboratory mouse; messenger RNA; polymerase chain reaction; pregnancy

Arylamine N-acetyltransferases (NATs) catalyze the acetylation of extracyclic amino groups of aromatic amine and hydrazines. Two genes, NAT 1 or NAT 2, each exhibit polymorphisms that result in variation in NAT activities. Associations between acetylator phenotype and susceptibility to aromatic amine toxicity are well-known in adults. Little has been reported on contributions of NAT to developmental toxicity. The overall goal of the study is to investigate the role of NAT genotypes in aromatic amine-induced developmental genotoxicity. The hypothesis is that elevated NAT activities will increase the risk of aromatic amine induced developmental genotoxicity. The specific aims to test this hypothesis are: 1) to determine if maternal expression of NAT genes changes during pregnancy; 2) to investigate NAT 1 and NAT 2 pre- and post-natally; and 3) to correlate NAT 2 genotype with embryonic/fetal toxicity of 4-aminobiphenyl (4-AB) or 2- aminofluorene (2-AF). C57Bl/6 mice are classified as rapid acetylators and will be used as the model for aims 1 and 2. NAT 1 and NAT 2 mRNAs will be assessed by RT-PCR in non-pregnant and pregnant females and embryos or neonates. The presence of functional NAT proteins will also be evaluated by measuring acetylation of substrates of both isoforms, as well as those selective and/or specific for NAT 1 or NAT 2. For aim 3, C57Bl/6 mice and the congenic strain B6.A will be used. These strains have the same NAT 1 but differ in NAT 2 alleles resulting in high (C57Bl/6) and low (B6.A) levels of NAT activity. Pregnant animals will be exposed to the carcinogen, 4-AB or 2-AF and DNA adducts in the conceptus determined with specific antibodies. The four possible combinations of maternal and embryonic genotypes will be tested. In order to separate the contribution of maternal and embryonic genotypes, embryos of the high activity strain will be transferred to the low activity strain and vice versa. The results of these studies will show whether inter-individual variation in NAT 2 is associated with developmental genotoxicity. Such information would be useful in understanding potential human risk pregnancy and development, by identifying susceptible genotypes.

芳胺 N-乙酰转移酶 (NAT) 催化芳香胺和肼的环外氨基的乙酰化。 NAT 1 或 NAT 2 这两个基因各自表现出多态性，导致 NAT 活性发生变化。乙酰化剂表型与对芳香胺毒性的易感性之间的关联在成人中是众所周知的。关于 NAT 对发育毒性的影响鲜有报道。该研究的总体目标是研究 NAT 基因型在芳香胺诱导的发育遗传毒性中的作用。假设 NAT 活性升高会增加芳香胺诱导的发育遗传毒性的风险。检验这一假设的具体目的是：1）确定母体NAT基因的表达在怀孕期间是否发生变化； 2) 产前和产后调查 NAT 1 和 NAT 2； 3) 将 NAT 2 基因型与 4-氨基联苯 (4-AB) 或 2-氨基芴 (2-AF) 的胚胎/胎儿毒性关联起来。 C57Bl/6 小鼠被归类为快速乙酰化小鼠，将用作目标 1 和 2 的模型。将通过 RT-PCR 在非怀孕和怀孕雌性以及胚胎或新生儿中评估 NAT 1 和 NAT 2 mRNA。功能性 NAT 蛋白的存在也将通过测量两种同工型底物的乙酰化以及对 NAT 1 或 NAT 2 具有选择性和/或特异性的底物的乙酰化来评估。对于目标 3，C57Bl/6 小鼠和同类品系 B6.A将被使用。这些菌株具有相同的 NAT 1，但 NAT 2 等位基因不同，导致 NAT 活性水平高 (C57Bl/6) 和低 (B6.A)。怀孕的动物会接触到致癌物、4-AB或2-AF以及用特异性抗体确定的概念中的DNA加合物。将测试母体和胚胎基因型的四种可能组合。为了区分母体和胚胎基因型的贡献，高活性菌株的胚胎将被转移到低活性菌株，反之亦然。这些研究的结果将表明 NAT 2 的个体间变异是否与发育遗传毒性相关。通过识别易感基因型，这些信息将有助于了解潜在的人类怀孕和发育风险。