GROWTH ARREST AND DNA DAMAGE INDUCIBLE GENE GADD153--REGULATION BY DNA DAMAGE

尽管所有细胞都对氧化应激和DNA损伤做出反应， 诱导许多基因，很少有人知道潜在的 在真核生物中参与这些反应的机制。 GADD 153是一种 CCAAT/增强子结合蛋白（C/EBP）相关基因，该基因可快速并 高度诱导响应各种压力，包括DNA 损伤和氧化应激，并提供了一个有用的模型， 引起对基因毒性反应的分子机制 应力 它是其他C/EBP的负调节因子 转录激活因子，因此可以发挥关键作用， 决定哪些其他基因表达或抑制，以响应 这些压力。 我们最近的研究集中在 介导响应DNA损伤的GADD 153的诱导， 氧化应激 与其他转录因子的转录激活相反， DNA损伤诱导基因，GADD 153诱导似乎涉及 既不是蛋白激酶C，也不是酪氨酸激酶，而是需要一个 未鉴定的丝氨酸-苏氨酸激酶，因此代表了一种独特的 在细胞对遗传毒性应激的反应中起重要作用。 此外，本发明还提供了一种方法， 基于它们对谷胱甘肽细胞水平的相对敏感性， 似乎氧化应激和DNA损伤调节转录， 通过不同的途径。 使用凝胶迁移率变动分析， 在GADD 153的启动子区鉴定了几个顺式元件， 其显示与核裂解物中存在的因子的结合增强 从用DNA损伤剂处理的细胞中制备。 这些是 可能代表转录因子的结合， 介导基因的转录激活，以响应 应力 探讨DNA损伤和/或修复能力之间的关系 和GADD 153的表达，我们检测了GADD 153的激活， 顺铂耐药与顺铂耐药HeLa细胞中的启动子 在用遗传毒性剂治疗后。 我们观察到， GADD 153在耐药细胞中的表达相对于敏感细胞 它们所来源的细胞。 这些发现支持了 GADD 153的表达与细胞对药物的敏感性有关。 DNA损伤剂的细胞毒性作用。

Although all cells respond to oxidative stress and DNA damage with the induction of numerous genes, little is known about the underlying mechanisms involved in these responses in eucaryotes. GADD153 is a CCAAT/enhancer-binding protein (C/EBP)-related gene that is rapidly and highly induced in response to a variety of stresses including DNA damage and oxidative stress and provides a useful model for examining the molecular mechanisms involved in eliciting the response to gentoxic stress. It is a putative negative regulator of other C/EBP transcriptional activators, and as such could play a key role in determining what other genes are expressed or repressed in response to these stresses. Our recent studies have concentrated on the pathways mediating the induction of GADD153 in response to DNA damage and oxidative stress. In contrast to transcriptional activation of other DNA damage inducible genes, GADD153 induction appears to involve neither protein kinase C nor tyrosine kinases, but rather requires an unidentified serine-threonine kinase, thus representing a unique pathway in the cellular response to gentoxic stress. In addition, based on their relative sensitivity to cellular levels of glutathione, it appears that oxidative stress and DNA damage regulate transcription through different pathways. Using gel mobility shift assays we have identified several cis elements in the promoter region of the GADD153 which show enhanced binding to factors present in nuclear lysates prepared from cells treated with DNA damaging agents. These are likely to represent binding of transcription factors important in mediating the gene's transcriptional activation in response to the stress. To explore the relationship between DNA damage and/or repair capacity and the expression of GADD153 we examined the activation of the GADD153 promoter in cisplatin-resistant versus cisplatin resistant HeLa cells following their treatment with the genotoxic agent. We observed lower GADD153 expression in the resistant cells relative to the sensitive cells from which they were derived. These findings support the notion that the expression of GADD153 is related to the cell's sensitivity to cytotoxic effects of the DNA damaging agent.