GAMMA GCS REGULATION--REGULATORY/CATALYTIC SUBUNIT GENES

非蛋白硫醇、谷胱甘肽(γ-谷氨酰半胱氨基-甘氨酸， GSH)是一种主要的细胞抗氧化剂，因此对 在维持细胞氧化还原平衡方面的功能，提供 对活性氧物种的保护，并参与了 外源物质的解毒作用可通过与 活性中间体或通过酶催化的偶联反应 谷胱甘肽S转移酶。细胞暴露于多个 异源生物制剂导致总量显著增加 转录上调次要的细胞内GSH含量 编码这两个蛋白质亚基的基因(催化和 谷氨酰半胱氨酸合成酶(GCS，EC 6.3.2.2)的调节)， 限速酶在从头合成中的作用。据推测， 两个GCS亚单位基因的转录上调涉及 相似的顺式元件，但反式因子的不同组合， 促进差异化监管，以应对特定的 诱导剂。转录被假设涉及二聚体 由小分子MAF蛋白和其他多种转录因子组成的转录因子 BZIP家族成员，包括Nrf1、Nrf2、Fos和Jun.此外， 转录激活被认为是由特定的 MAPK信号通路在细胞氧化还原反应中的作用 平衡有利于更有利于氧化的状态。在评估这些方面 根据假设，我们提出以下具体目标：1.最终确定 重亚基和轻亚基启动子中顺式元素的分析 以确定与基因转录激活有关的基因 对β-核因子、tBOOH、甲萘二酮、H202和PDTC的反应。2.识别 反式激活因子及其组成蛋白是 最终参与与确定的特定顺式元件的结合 目标1.3：确定氧化应激在GCS中所起的作用 亚单位基因诱导。4.明确涉及的信号通路(S) 上调GCS亚单位基因。 该申请提出了一项全面调查 信号、信号通路、反式和顺式因子 它们共同构成了GCS基因调控的机制 本构条件和响应的选择类 包括在调查中的特工。

The non-protein thiol, glutathione (gamma-glutamyl-cysteinyl-glycine, GSH) is a predominant cellular antioxidant and as such serves critical functions in the maintenance of cellular redox balance, provides protection against reactive oxygen species and is involved in the detoxication of xenobiotics either through direct reactions with reactive intermediates or via enzymatic conjugation reactions catalyzed by glutathione S-transferases. Exposure of cells to a number of xenobiotic agents results in a significant increase in the total intracellular GSH content, secondary to transcriptional up-regulation of the genes encoding the two protein subunits (catalytic and regulatory) of gamma-glutamylcysteine synthetase (GCS, EC 6.3.2.2), the rate-limiting enzyme in its de novo synthesis. It is hypothesized that transcriptional up-regulation of the two GCS subunit genes involves similar cis-elements, but distinct combinations of trans- factors, contributing to differential regulation in response to specific inducting agents. Transcription is hypothesized to involve dimeric transcription factors composed of small Maf proteins and various other bZIP family members, including Nrf1, Nrf2, Fos and Jun. Furthermore, transcriptional activation is hypothesized to be mediated by specific MAPK signaling pathways in response to alterations in the cellular redox balance in favor of a more pro-oxidant state. In evaluating these hypotheses, we propose the following Specific Aims: 1. Finalize analysis of cis- elements within the heavy and light subunit promoters to identify those involved in transcriptional activation of the genes in response to beta-NF; tBOOH; menadione, H202 and PDTC. 2. Identify the transactivating factors and their component proteins which are ultimately involved in binding to the specific cis- elements identified in Aim 1. 3. Determine the role that oxidative stress plays in GCS subunit gene induction. 4. Define the signaling pathway(s) involved in up-regulation of GCS subunit genes. The application proposes a comprehensive investigation of the nature of the signals, the signaling pathways, and the trans- and cis- factors which in composite constitute the mechanism of GCS gene regulation under constitutive conditions and in response to the selective classes of agents included in the investigation.