BIOLOGICALLY SIGNIFICANT DAMAGE IN DNA

我们已经提出了DNA双链断裂的机制 (DSB)产生据称具有重大生物学意义的损害(1) 通过细胞内电离辐射(2)。这些机制可以预测 其他局部倍增破坏站点(LMD)产生于 其中没有出现断股损伤。据预测，这些将 以比实际DSB更高的成品率成形。个人 LMDS的组成损坏位置可以产生、分离在 相对较长距离的DNA相反的链 分子水平，高达10+个碱基对。如此相隔甚远 受损地点可以像修复单个受损地点一样进行修复 这样，土地就不会对细胞构成危险，即使它们会 在通常的检测中，检测结果为LMDS。 在拟议的工作中，我们的目标是衡量各种不同 最初使用SV 40 DNA的模型系统中的LMD类型 保护到与电池中相同的OH‘清除状态的溶液 然后是染色质中的SV 40，然后在哺乳动物细胞内。这个 然后将SV 40 DNA的反应与细胞的反应进行比较 使用非洲绿的α串联重复序列的DNA 猴子当模特。然后我们将确定分配给 对立面上LMDS组成损伤的分离 DNA链，最初也是与SV 40型号系统一起使用，然后 如上所述扩展到蜂窝系统。终于过了 全面发展阿尔法DNA检测，我们将探索 细胞修复各种类型的LMD(非链)的能力 断裂VS链断裂，短分离VS长)。因此，我们希望 为了清楚地定义各种严重的DNA损伤，必须 在维修过程中要考虑。这将有助于设计一种特定的 重大损伤的检测和指定的酶 可以修复它们的过程。

We have suggested mechanisms whereby the DNA double strand break (DSB) the purported biologically significant lesion (1) is produced intracellularly by ionizing radiation (2). The mechanisms predict that other locally multiply damaged sites (LMDS) are produced in which none strand break damage is present. These are predicted to be formed in greater yield than actual DSBs. The individual constituent damage sites of an LMDS can be produced, separated on the opposite strands of the DNA by relatively large distances on the molecular level, up to 10+ base pairs. Such well separated damage sites could be repaired as if they were singly damaged sites land would then not be hazardous to the cell even though they would assay as LMDS in the usual assays. In the proposed work, we aim to measure the yields of the various types of LMDS in model systems initially using SV 40 DNA in solution protected to the same OH' scavenging state as in the cell and then SV 40 in chromatin then within the mammalian cell. The response of the SV 40 DNA will then be compared to that of cellular DNA using the alpha tandem repeat sequence of the African green monkey as a model. We will then determine the distribution of separation of the constituent damages of LMDS on the opposite Strands of DNA, again initially with the SV 40 model system, then extending to the cellular system as described above. Finally after developing the assay of alpha DNA fully, we will explore the ability of cells to repair the various types of LMDS (non-strand break vs strand break, short separation vs long). Thus, we hope to define clearly the variety of significant DNA damage which must be considered during repair. This will aid in devising a specific assay for significant damage and in assigning the enzymatic processes by which they can be repaired.