ULTRAVIOLET DAMAGE REPAIR IN BACILLUS SUBTILIS SPORE DNA

遗传物质经常受到太阳紫外线的影响。 辐射(UV)和生物将高度优先放在 纠正潜在的致命性或诱变性紫外线诱导的DNA损伤。它 早就知道，患有相对罕见疾病的人 遗传性DNA修复障碍，如着色性干皮病，表现为紫外线 过敏症和皮肤癌的高发病率。最近， 观测到的陆地紫外线暴露增加与 大气臭氧破坏，以及人类皮肤发病率的增加 癌症，凸显学习基础健康的重要意义 细胞修复紫外线损伤DNA的机制。 芽孢杆菌属和梭状芽孢杆菌属的细菌产生孢子，它们是 抗紫外线杀伤力是营养植物的10-100倍 细胞。细菌孢子的抗紫外线能力是由于(I)独特的 孢子DNA的光化学和(Ii)萌发孢子的能力 精准修复这种独特的DNA损伤，被称为“孢子感光产物”， 或SP，通过使用两个主要修复系统，其中一个显然是 特定于SP。现有的证据有力地证明了 B型和A型之间的DNA螺旋在产孢子和 在SP产生和随后的修复过程中的萌发。 这个项目的长期目标是阐明结构， 芽孢杆菌中SP特异性DNA修复系统的调控及其机制 枯草杆菌称为SPL。自提交第一份申请以来，DNA 纠正SPL系统中的突变已被克隆，并定位在B。 枯草杆菌染色体，并进行序列测定；SPL基因序列编码一个40 在当前的序列数据库中没有同源的千道尔顿蛋白质。这个 该应用程序修订版的目标是：确定 Sp1基因的顺式作用调控位点(S)和相应的 交易因素；调查这些监管组成部分是如何 交互以指导正确的时间和隔间表达 产孢子过程中的基因(S)；酶的鉴定和纯化(S) 参与SP修复，并克隆可能的额外SPL基因；以及 研究SP修复反应的机理和要求 在体外，使用提纯的成分。

The genetic material is constantly subjected to solar ultraviolet radiation (UV), and living organisms place a high priority on the correction of potentially lethal or mutagenic UV-induced DNA damage. It has long been known that individuals afflicted with relatively rare heritable DNA repair disorders such as xeroderma pigmentosum exhibit UV hypersensitivity and a high incidence of skin cancer. More recently, the observed correlation between increased terrestrial UV exposure due to atmospheric ozone destruction, and an increasing incidence of human skin cancer, highlight the health-related significance of studying basic mechanisms by which cells repair UV damage to their DNA. Bacteria of the genera Bacillus and Clostridium produce spores which are 10-100 fold more resistant to killing by UV than vegetatively growing cells. UV resistance of bacterial spores is due to (i) the unique photochemistry of spore DNA and (ii) the ability of germinating spores to accurately repair this unique DNA damage, known as "spore photoproduct", or SP, by using two major repair systems, one of which is apparently specific for SP. The available evidence strongly implicates shifting of the DNA helix between the B-form and an A-like form during sporulation and germination in the production and subsequent repair of SP. The long-range objective of this project is to elucidate the structure, regulation, and mechanism of the SP-specific DNA repair system in Bacillus subtilis called spl. Since submission of the first application, DNA correcting a mutation in the spl system has been cloned, mapped on the B. subtilis chromosome, and sequenced; the spl gene sequence encodes a 40 kilodalton protein with no homolog in the current sequence databases. The objectives of this revised version of the application are: identifying both the cis-acting regulatory sites of the spl gene(s) and corresponding trans-acting factors; investigating how these regulatory components interact to direct the proper temporal and compartmental expression of the gene(s) during sporulation; identifying and purifying the enzyme(s) involved in SP repair, and cloning possible additional spl genes; and studying the mechanism and requirements of the SP repair reaction in vitro, using purified components.