ENVIRONMENTAL ULTRAVIOLET LIGHT AND CYTOSKELETAL DAMAGE

由于太阳紫外线（UV）光是皮肤的主要原因 癌症，重要的是要确定紫外线诱导的细胞病变 这可能有助于致癌过程。 除了 探讨了紫外线对DNA损伤的作用， 还必须考虑其它细胞组分的改变。 本研究的目的是调查 细胞骨架是由培养的细胞暴露于 与环境相关的紫外线波长。 的 选择细胞骨架进行研究，因为它是一种 正常细胞生长调节的重要参与者， 这种复杂的细胞质结构的破坏可能导致 有害的细胞功能障碍 正常人皮肤成纤维细胞和表皮角质形成细胞 将使用在不同生长条件下培养的菌株 表征UV光诱导的细胞骨架变化， 微管、微丝和中间丝。 多色紫外光照射下细胞骨架的变化 由环境相关的波长组成，或者更多 将研究常用的短波长（254 nm）UV光 通过荧光显微镜。 角质形成细胞的细胞骨架 在不同的阶段进行紫外线照射， 还将研究差异。 此外该 干皮病患者成纤维细胞的细胞骨架 色素沉着症、布卢姆综合征和科凯恩综合征将是 研究以确定细胞骨架损伤是否可能 有助于细胞的光敏性。 已经确定 长波长的紫外线会破坏正常人的微管， 细胞，将进行实验以区分 微管损伤导致的微管破裂 辐照前组装或未组装的变更 二聚体微管蛋白亚基。 这将通过检查 紫外光对提取的细胞骨架的影响， 微管蛋白在仅含有微管的细胞中的再聚合 微管蛋白的二聚体形式。 的作用 活性氧在改变细胞骨架形成中的作用 也将被探索。 此外，从UV提取的微管蛋白 将使用SDS检查辐照细胞和对照细胞 聚丙烯酰胺凝胶电泳，以确定是否UV 光诱导形成高分子量、交联的 微管蛋白

Since solar ultraviolet (UV) light is the major cause of skin cancer, it is important to identify the UV induced cellular lesions which may contribute to the carcinogenic process. In addition to pursuing the role of DNA damage, the importance of UV induced alterations of other cellular components must also be considered. It is the aim of the current study to investigate disruption of the cytoskeleton resulting from exposure of cultured cells to environmentally relevant wavelengths of UV light. The cytoskeleton has been selected for investigation since it is an important participant in the regulation of normal cell growth, and disruption of this complex cytoplasmic structure may result in detrimental cellular dysfunctions. Normal human skin fibroblast and epidermal keratinocyte cell strains, cultured under varying growth conditions, will be utilized to characterize UV light induced alterations of cytosketetal microtubules, microfilaments and intermediate filaments. Cytoskeletons of cells exposed to polychromatic UV light composed of environmentally relevant wavelengths or to the more commonly used short wavelength (254 nm) UV light will be studied by fluorescence microscopy. The cytoskeleton of keratinocytes which have been UV irradiated at different stages of differentiation will also be examined. In addition, the cytoskeleton of fibroblasts derived from patients with xeroderma pigmentosum, Bloom's syndrome and Cockayne's syndrome will be investigated in order to determine if cytoskeletal damage may contribute to the photosensitivity of cells. Having determined that long wavelength UV light disrupts microtubules in normal cells, experiments will be performed to differentiate between the disruption of microtubules resulting from damage to microtubules assembled prior to irradiation or from changes in unassembled dimeric tubulin subunits. This will be accomplished by examining the effect of UV light on extracted cytoskeletons and by studying the repolymerization of tubulin in cells which contain only the dimeric form of tubulin at the time of irradiation. The role of reactive oxygen species in the formation of altered cytoskeletons will also be explored. Furthermore, tubulin extracted from UV irradiated and control cells will be examined using SDS polyacrylamide gel electrophoresis in order to determine if UV light induces the formation of high molecular weight, cross-linked tubulin.