MUTAGENESIS BY METALS OF ENVIRORMENTAL SIGNIFICANCE

金属化合物的遗传效应一直很难确定 学习。启用更改暴露方案和遗传终结点 本实验室检测一些金属化合物的致突变性。 其他化合物，虽然本身不会致突变，但可以增强 紫外线(UV)的致突变性。这项提案将解决 这两种现象的发生机制。由于影响了 DNA上的铬和镍已经被其他人很好地研究了， 该项目的重点将是阐明通过以下方式对DNA的影响 铜、铅、铁的致突变或共致突变化合物， 锰、砷、钼、钨和锌(按顺序 优先)单独使用或使用紫外线照射。 金属化合物破坏DNA或增强紫外线的能力 诱导损伤，将使用测序凝胶技术进行研究。 链断裂部位、碱性、DNA修复酶 识别和聚合酶抑制将在AT上确定 在大肠杆菌gpt编码中至少有一个限制性片段 序列。初步数据表明，在某些情况下(例如 Cu2+)，协同诱变效应可能是由羟基自由基介导的。 由芬顿反应形成，导致随机链断裂，这可能 被KI抑制。如果特定的损坏位置是 确定后，损伤的性质将通过以下方式确定 物理化学手段。对细胞DNA的影响将是 研究那些不会损伤质粒DNA的金属化合物 或者使用碱性洗脱技术来增强紫外线诱导的损伤。 此外，还将研究金属化合物破坏DNA的能力。 通过基因手段。质粒pSV2 gpt将被处理，并且 转染率和突变率(对gpt-)将为 以中国仓鼠V79 HPRT细胞为宿主进行测定。在……里面 此外，稳定的V79(Gpt)转染体的诱变将是 进行，并将测量大规模删除的频率。 预计该基因座的突变将会更多 对多位点缺失敏感(已知由氧化引起 损伤)与内源性HPRT基因座进行比较。 利用相同的遗传靶点(E.coligpt)进行DNA研究 损伤部位和突变最终将使 确定特定类型的生物燃料的诱变后果 损坏。

The genetic effects of metal compounds have been difficult to study. Altering exposure protocols and genetic endpoints enabled this laboratory to detect the mutagenicity of some metal compounds. Other compounds, while not mutagenic per se, could enhance the mutagenicity of ultraviolet light (UV). This proposal will address the mechanisms for these two phenomena. Since the effects of chromium and nickel on DNA have been well studied by others, the focus of this project will be to elucidate the effects on DNA by mutagenic or comutagenic compounds of copper, lead, iron, manganese, arsenic, molybdenum, tungsten and zinc (in order of priority) either alone or with UV irradiation. The ability of metal compounds to damage DNA, or to enhance UV- induced damage, will be studied using sequencing gel techniques. Sites of strand breaks, alkali-lability, DNA repair enzyme recognition and polymerase inhibition will be determined on at least one restriction fragment within the E. coli gpt coding sequence. Preliminary data suggests that in some cases (e.g. Cu2+), the comutagenic effect may be mediated by hydroxyl radicals formed by a Fenton reaction causing random strand breaks which can be inhibited by KI. In cases where specific sites of damage are identified, the nature of the lesions will be determined by physical chemical means. The effects on cellular DNA will be studied for those metal compounds which do not damage plasmid DNA or enhance UV-induced damage, using alkaline elution techniques. The ability of metal compounds to damage DNA will also be studied by genetic means. The plasmid pSV2 gpt will be treated, and the transfection frequency and mutation frequency (to gpt-) will be determined using Chinese hamster V79 hprt- cells as a host. In addition, mutagenesis of a stable V79 (gpt) transfectant will be carried out, and the frequency of large deletions will be measured. It is expected that mutagenesis at this locus will be more sensitive to multi-locus deletions (known to be caused by oxidative damage) compared to the endogenous hprt locus. Using the same genetic target (E. coli gpt) for the studies on DNA damage sites and mutagenesis will ultimately enable the determination of the mutagenic consequences of specific types of damage.