TRANSCRIPTIONAL ACTIVATION OF EARLY-RESPONSE GENES BY HYDROGEN-PEROXIDE IN A MOUSE OSTEOBLASTIC CELL-LINE
TRANSCRIPTIONAL ACTIVATION OF EARLY-RESPONSE GENES BY HYDROGEN-PEROXIDE IN A MOUSE OSTEOBLASTIC CELL-LINE
复制标题
DOI：
10.1111/j.1432-1033.1991.tb16261.x
复制
发表时间：
1991-10-01
期刊：
影响因子：
--
通讯作者：
KUROKI, T
中科院分区：
文献类型：
--
作者：
NOSE, K;SHIBANUMA, M;KUROKI, T
与其他氧化剂一样，已知H2 O2在低浓度下在静息Balb/3 T3或小鼠表皮JB 6细胞中充当有丝分裂原。我们以前描述过H2 O2诱导Balb/3 T3细胞中的一些早期反应基因。我们使用另一种细胞系，MC 3 T3（小鼠成骨细胞）细胞，通过检查这些基因的转录活性和使用蛋白激酶抑制剂来扩展这些观察结果。H_2O_2可使c-fos、c-jun、JE-1和JE基因的表达增加，这些基因是已知的早期反应基因，在许多类型的细胞中由促有丝分裂刺激诱导。外源性添加H2 O2增加了这些基因的mRNA水平，增加的动力学类似于它们的诱导由佛波酯或血清。细胞核连续转录表明，这种诱导发生在转录水平。H2 O2在0.1-0.2 mM诱导c-fos和c-jun的最大表达，而0.3 mM H2 O2是诱导应激诱导的血红素加氧酶mRNA所必需的。c-fos和c-jun的诱导被50 μ M的H7抑制，H7是一种对蛋白激酶C相对特异的蛋白激酶抑制剂，但不受H9的影响，H9对cAMP依赖的蛋白激酶相对特异。然而，在用12-O-tetradecanoylphorbol 13-acetate预处理的细胞中，其中蛋白激酶应该被下调，H2 O2诱导c-fos和血红素加氧酶与未处理的细胞一样有效。H2 O2不增加p80蛋白的磷酸化，p80蛋白是蛋白激酶C的底物。因此，H2 O2似乎通过激活不同于蛋白激酶C的蛋白激酶来诱导c-fos和c-jun。氯霉素乙酰转移酶基因的活性控制下的血清反应元件的人c-fos基因的H2 O2处理增加，而控制下的cAMP反应元件不受影响。这些结果表明，诱导过氧化氢的c-fos和其他可能的早期反应基因介导的血清反应元件在其增强子的激活。
H2O2, like other oxidants, is known to act as a mitogen at low concentrations in resting Balb/3T3 or mouse epidermal JB6 cells. We described previously that H2O2 induces some early response genes in Balb/3T3 cells. We extended these observations using another cell line, MC3T3 (mouse osteoblastic) cells by examination of transcriptional activity of these genes and by using inhibitors of protein kinases. H2O2 increased the expressions of c-fos, c-jun, egr-1 and JE genes which are known to be early response genes and are induced by mitogenic stimuli in many types of cells. Exogenous addition of H2O2 increased the mRNA levels of these genes, the kinetics of increase being similar to those of their inductions by a phorbol ester or serum. Nuclear run-on transcription showed that this induction occurred at the transcriptional level. H2O2 at 0.1-0.2 mM induced maximal expressions of c-fos and c-jun, whereas 0.3 mM H2O2 was required for induction of stress-induced heme oxygenase mRNA. The inductions of c-fos and c-jun were inhibited by 50-mu-M H7, a protein kinase inhibitor that is relatively specific for protein kinase C, but were not affected by H9, relatively specific for cAMP-dependent protein kinase. In cells pretreated with 12-O-tetradecanoylphorbol 13-acetate, however, in which protein kinase was supposed to be downregulated, H2O2 induced c-fos and heme oxygenase as efficiently as in untreated cells. H2O2 did not increase the phosphorylation of p80 protein, which is known to be a substrate for protein kinase C. Thus, H2O2 seemed to induce c-fos and c-jun by activating protein kinases distinct from protein kinase C. Activity of the chloramphenicol acetyltransferase gene under control of the serum-response element of human c-fos genes was increased by H2O2 treatment, whereas that under control of cAMP-response element was not affected. These results indicate that the inductions by H2O2 of c-fos and possibly other early response genes are mediated through activation of the serum-response element in their enhancer.