Enzymatic Repair of DNA Damage in Plants

近年来，平流层臭氧的显著消耗 导致紫外线（UV）辐射增加， 地球的表面。 随着这种增长，关注和兴趣 关于紫外线辐射对人体有什么具体影响， 生物体中的细胞过程。 其中一个影响是， DNA，已在细菌和哺乳动物中被广泛研究 然而，关于紫外线辐射影响的信息有限。 植物细胞对DNA的损伤及其体内修复 机制等 该提案描述了对一个环的初步研究- 在植物细胞中发现的饱和嘧啶切割活性 抗紫外线照射或氧化的DNA。 这种酶活性 将从甘蓝（花椰菜）中纯化， 常规技术包括离子交换、亲和和凝胶 过滤色谱法 底物对UV- 辐射或氧化的放射性标记的多脱氧核糖核苷酸 将通过高压液相色谱法表征 （HPLC）。 用纯化的酶作探针， 碱基序列对这些病变的形成及其 随后的体内修复将被量化。 以来 叶绿体基因组也容易受到损伤， 叶绿体中环饱和嘧啶-DNA修复酶 将进行调查。 这将决定是否有一种方法 为了有效地从叶绿体DNA中去除这种受损的病变， 保持遗传物质的完整性。 的结果 这些研究应有助于更好地了解 构成植物细胞的生化过程 DNA损伤的反应。 目的是最终使用 从这个项目中获得的知识，以分离植物菌株 它们有更强的修复能力， 辐射和氧化，因此具有增加的存活率 容量

In recent years, a marked depletion of stratospheric ozone has caused an increase in ultraviolet (UV) radiation reaching the surface of the Earth. With this increase, concern and interest has been raised as to what specific effects UV radiation has on cellular processes in organisms. One such effect, the damage of DNA, has been extensively investigated in bacterial and mammalian systems; however, limited information exists on the effects of UV damage to plant DNA and its in vivo repair by cellular mechanisms. This proposal describes the initial study of a ring- saturated pyrimidine incising activity found in plant cells against UV irradiated or oxidized DNA. This enzymatic activity will be purified from Brassica oleracea (cauliflower) by conventional techniques including ion-exchange, affinity, and gel filtration chromatography. The substrate specificity against UV- irradiated or oxidized, radiolabeled polydeoxyribonucleotides will be characterized by high pressure liquid chromatography (HPLC). Using the purified enzyme as a probe, the effects of DNA base sequence on the formation of these lesions and their subsequent in vivo repair will be quantified. Since the chloroplast genome is also susceptible to damage, the presence of the ring-saturated pyrimidine-DNA repair enzyme in chloroplasts will be investigated. This should determine if there is a means to effectively remove this damaged lesion from chloroplast DNA to maintain the integrity of this genetic material. The results of these studies should lead to a better understanding of the biochemical processes that constitute the plant cellular response to DNA damage. The aim is to ultimately use the knowledge obtained from this project to isolate plant strains that have an increased ability to repair damage caused by radiation and oxidation and therefore have an increased survival capacity.