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

生长停滞和 DNA 损伤诱导基因 GADD153——DNA 损伤的调节

• 批准号: 3789876
• 负责人: N J HOLBROOK
• 金额: --
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3789876
• 关键词: DNA damage; calcium flux; cell growth regulation; enzyme inhibitors; gene expression; gene induction /repression; phosphatase inhibitor; protein kinase; stress proteins; transcription factor

gadd153 is a mammalian gene whose expression is increased in response to a variety of stresses including DNA damage and growth arrest. It encodes a 19 kd protein with homology to the CCAAT/enhancer-binding protein (C/EBP) family of transcription factors. This family consists of at least 5 members which contain a conserved bZIP carboxyl-terminal domain. The bZIP domain consists of a basic region involved in DNA recognition and binding, and an adjacent leucine zipper region, that mediates subunit dimerization. gadd153 is unique among C/EBP-related proteins in that it cannot bind to DNA. However, it can form stable heterodimers with C/EBP proteins and prevent their DNA-binding, suggesting that gadd153 acts as an inhibitor of these transcriptional activators. The functional significance of these interactions and their relationship to elevated gadd153 expression following stress is unclear, but we have recently shown that two other C/EBP-related proteins, C/EBPa, and C/EBP6, are also induced by DNA damage. We have examined the role of calcium as a second messenger in regulating gadd153 expression and have found that treatment of cells with the calcium ionophore A23187 leads to the rapid induction of gadd153 mRNA. Elevated mRNA levels result from both an increase in the rate of gadd153 transcription and an enhanced stability of gadd153 mRNA. Buffering intracellular calcium by treatment with BAPTA-AM prevents gadd153 induction by both A23187 and the DNA alkylating agent MMS. Thus, it is likely that intracellular calcium plays a role in controlling gadd153 expression following DNA damage. Inhibitors of various protein kinase and phosphatases have also been tested for their ability to influence gadd153 expression following DNA damage. Protein kinase C inhibitors failed to inhibit gadd153 mRNA induction as well as gadd153 promoter activation by MMS. Tyrosine kinase inhibitors (genestein and vanadate) were also without effect. However, two general kinase inhibitors, 2-aminopurine and H7, both blocked gadd153 mRNA expression. Okadaic acid and calyculin, specific inhibitors of phosphatases 1 and 2A, induced gadd153 mRNA expression and enhanced gadd153 promoter activity. Thus, gadd153 appears to be under control of both protein kinase(s) and phosphatase(s), although the specific enzymes remain to be identified.

gadd153 是一种哺乳动物基因，其表达会随着 各种应激，包括 DNA 损伤和生长停滞。 它 编码与 CCAAT/增强子结合同源的 19 kd 蛋白质 转录因子蛋白 (C/EBP) 家族。 这个家庭包括 至少 5 个成员包含保守的 bZIP 羧基末端 领域。 bZIP 结构域由涉及 DNA 的基本区域组成 识别和结合，以及相邻的亮氨酸拉链区域， 介导亚基二聚化。 gadd153 在 C/EBP 相关中是独一无二的 蛋白质，因为它不能与 DNA 结合。 但可以形成稳定的 与 C/EBP 蛋白的异二聚体并阻止其 DNA 结合，表明 gadd153 充当这些转录激活因子的抑制剂。这 这些相互作用的功能意义及其与 应激后 gadd153 表达升高尚不清楚，但我们有 最近表明，另外两种 C/EBP 相关蛋白 C/EBPa 和 C/EBP6， 也由DNA损伤引起。 我们研究了钙作为第二信使在调节中的作用 gadd153 表达并发现用钙处理细胞 离子载体 A23187 导致 gadd153 mRNA 的快速诱导。 高架 mRNA 水平是由 gadd153 速率的增加引起的 gadd153 mRNA 的转录和增强的稳定性。 缓冲 用 BAPTA-AM 处理细胞内钙可预防 gadd153 由 A23187 和 DNA 烷化剂 MMS 诱导。 因此，它是 细胞内钙可能在控制 gadd153 中发挥作用 DNA 损伤后的表达。 各种蛋白激酶和磷酸酶的抑制剂也已被 测试其影响 DNA 后 gadd153 表达的能力 损害。 蛋白激酶 C 抑制剂未能抑制 gadd153 mRNA MMS 诱导以及 gadd153 启动子激活。 酪氨酸激酶 抑制剂（染料木黄酮和钒酸盐）也没有效果。 然而， 两种通用激酶抑制剂，2-氨基嘌呤和 H7，均阻断 gadd153 mRNA 表达。 冈田酸和花萼蛋白，特异性抑制剂 磷酸酶 1 和 2A，诱导 gadd153 mRNA 表达并增强 gadd153 启动子活性。 因此，gadd153 似乎受到控制 蛋白激酶和磷酸酶，尽管特定的酶 仍有待确定。