Murphy B J, Laderoute K R, Chin R J, Sutherland R M
Cell and Molecular Biology Laboratory, SRI International, Menlo Park, California 94025.
Cancer Res. 1994 Nov 15;54(22):5808-10.
The expression of metallothionein IIA (MT-IIA) was investigated in A431 human squamous carcinoma cells exposed to hypoxia (pO < or = 0.01% of atmospheric pO2) and subsequent reoxygenation. Northern analysis showed that MT-IIA mRNA levels were significantly increased during 14 h of hypoxia and during reoxygenation. Western blotting confirmed that total MT protein levels were also increased in response to these stresses. Evidence of the transcriptional control of MT-IIA expression in hypoxic and in reoxygenated A431 cells was found using a 0.2-kilobase sequence of the proximal 5'-regulatory region of the MT-IIA gene in a chloramphenicol acetyltransferase reporter gene construct. Thus the proximal promoter of the human MT-IIA gene appears to contain a hypoxic response element(s). These observations indicate that MT-IIA may have an important role in the stress responses of cells in solid tumors.
研究了金属硫蛋白IIA（MT-IIA）在暴露于低氧（pO≤大气pO2的0.01%）及随后复氧的A431人鳞状癌细胞中的表达。Northern分析显示，在低氧14小时期间及复氧期间，MT-IIA mRNA水平显著升高。蛋白质免疫印迹证实，总MT蛋白水平也因这些应激而升高。使用MT-IIA基因近端5'-调控区的0.2千碱基序列构建氯霉素乙酰转移酶报告基因载体，发现了低氧和复氧的A431细胞中MT-IIA表达的转录调控证据。因此，人MT-IIA基因的近端启动子似乎含有一个低氧反应元件。这些观察结果表明，MT-IIA可能在实体瘤细胞的应激反应中起重要作用。
