CHROMATIN REPLICATION AND HEAT-INDUCED CELL DEATH

拟议研究的总体目标是确定 高温和辐射对哺乳动物细胞核的损伤 结构和功能;并确定这种损伤在 高温和辐射诱导染色体畸变诱导，细胞 灭活和放射增敏。 关于核武器的作用， 在细胞失活的结构改变，我们将确定的程度， 高温和辐射改变了 染色质复制方面，包括：DNA合成（复制子 新生DNA的起始、链延伸和连接延伸 进入亲本DNA），核组蛋白和基质蛋白的合成， 复制叉处染色质的加工和 在复制染色质中的高级结构。 相关性将是 在同步S期系统中，在任何病变的诱导之间， 在染色质复制和染色体畸变诱导中， 细胞失活 热疗和放射治疗对大鼠肝细胞凋亡影响的研究 两个额外的核现象（核被膜的结构和 核糖体RNA的合成/加工）。 关于 辐射敏感性，我们将确定染色质的作用， 结构，包括复制和转录活性，或 核糖体染色质DNA，在DNA的分布胸腺嘧啶碱基损伤和 它的修复。 我们还将确定核内分布 选定的DNA修复和复制酶，包括α和β 聚合酶和参与切除胸腺嘧啶碱基损伤的酶， 并确定高温暴露对活动的影响， 这些酶的分布。

The overall objectives of the proposed research is to determine the extent of hyperthermia and radiation-induced damage to the mammalian cell nuclear structure and function; and to determine the role of this damage in hyperthermia and radiation-induced chromosome aberration induction, cell inactivation and radiosensitization. With regard to the role of nuclear structure alterations in cell inactivation, we will determine the extent to which hyperthermia and radiation alters the structural and functional aspects of chromatin replication, including: DNA synthesis (replicon initiation, chain elongation and the ligation elongation of nascent DNA into parental DNA), synthesis of nuclear histones and matrix proteins, the processing of chromatin at the replication fork and the acquisition of higher order structure in replicating chromatin. A correlation will be made, in a synchronous S phase system, between the induction of any lesions in the replication of chromatin and both chromosome abrration induction and cell inactivation. Studies on the effect of hyperthermia and radiation on two additional nuclear phenomena (the structure of the nuclear envelope and the synthesis/processing of ribosomal RNA) will be initiated. With regard to radiation sensitivity, we will determine the role of chromatin structure(s) including replicating and transcriptionally active or ribosomal chromatin DNA, in the distribution of DNA thymine base damage and its repair. We will also determine the intranuclear distribution of selected DNA repair and replication enzymes, including Alpha and beta polymerase and the enzyme involved in the excission of thymine base damage, and determine the effect of hyperthermic exposure of the activity and distribution of these enzymes.