PHOTOINDUCED DNA PROTEIN CROSS LINKING IN CHROMATIN

由紫外线引起的细胞DNA的辐射损伤涉及一种 组件进程的数量。 其中之一是交联 染色体蛋白质转化为DNA 这项建议一般涉及 本发明的目的在于阐明真核细胞中UV辐射损伤的这一方面。 的 拟议的实验旨在实现对 紫外光诱导的DNA-蛋白质交联的化学基础，并评估 单个核碱基-氨基酸加合物的重要性， 作为观察到的蛋白质总交联的贡献者， 真核生物染色质中的DNA。 具体而言，拟议的研究将 试着回答以下问题：哪些氨基酸和核碱基 特别是参与组蛋白的光交联，和 染色体蛋白质，在一般情况下，DNA通过共价加合物形成？ 这些加合物的定量产率是多少，作为紫外线剂量的函数 对光交联的贡献最大 回答这些问题的方法如下。 一组 选择核碱基-氨基酸加合物，因为它们被认为是 潜在的重要性，在DNA-蛋白质交联，将准备通过 涉及DNA或同聚核苷酸与氨基酸或 或者，通过核碱基或核苷与 合适的氨基酸衍生物。 这些加合物将被表征为： 它们的化学、色谱和光谱特性。 使用 这方面的知识，他们将寻求在水解物的紫外线照射 核小体或真核染色质。 加合物的定量将是 通过使用化学衍生化的交联的 DNA-蛋白质复合物，结合高性能液体 已知加合物的色谱和化学衍生标准品 浓度.

Radiation damage to cellular DNA, induced by ultraviolet light, involves a number of component processes. One of these is the cross-linking of chromosomal proteins to DNA. This proposal is generally concerned with elucidation of this aspect of UV radiation damage in eukaryotic cells. The proposed experiments are designed to achieve an understanding of the chemical basis of UV light-induced DNA-protein cross-linking and to assess the importance of individual nucleobase-amino acid adducts, as a function of UV dose, as contributors to the total observed cross-linking of protein to DNA in eukaryotic chromatin. Specifically, the proposed research will try to answer the following questions: Which amino acids and nucleobases particiipate in the photocross-linking of histones, in particular, and chromosomal proteins, in general, to DNA via covalent adduct formation? What are the quantitative yields, as a function of UV dose of those adducts that are the most important as contributors to the photocrosss-linking? The approach to be used in answering these questions is as follows. A set of nucleobase-amino acid adducts, selected because they are deemed of potential importance in DNA-protein cross-linking, will be prepared via routes involving reaction of DNA or homopolynucleotide with amino acid or alternatively, through reaction of nucleobase or nucleoside with an appropriate amino acid derivative. These adducts will be characterized as to their chemical, chromatographic and spectroscopic properties. Using this knowledge, they will be sought in hydrosylates of UV-irradiated nucleosomes or eukaryotic chromatin. Quantitation of adducts will be achieved via use of chemically derivatized hydrosylates of cross-linked DNA-protein complexes, in conjunction with high performance liquid chromatography and chemically derivatized standards of known adduct concentration.