Fazzone H, Wangner A, Clerch L B
Department of Pediatrics, Georgetown University Medical Center, Washington, DC 20007.
J Clin Invest. 1993 Sep;92(3):1278-81. doi: 10.1172/JCI116700.
It has become increasingly clear that RNA-binding proteins play an important role in the regulation of gene expression. The presence in rat lung of a specific, redox-sensitive catalase RNA-binding protein was recently reported (Clerch, L. B., and D. Massaro, 1992. J. Biol. Chem. 267:2853). In order to determine if specific manganese superoxide dismutase (MnSOD) RNA-binding proteins exist, we tested whether protein in rat lung extract would bind to 32P-labeled MnSOD RNA. Using a gel mobility shift assay we show rat lung protein forms specific complexes with a 216 b fragment of the 3' untranslated region of MnSOD RNA and the binding requires the presence of free sulfhydryl groups. Competition studies indicate MnSOD RNA-binding protein is different from catalase RNA-binding protein. Furthermore, unlike catalase RNA-binding protein, rat lung MnSOD RNA-binding protein activity is developmentally regulated; there is less MnSOD RNA-protein binding activity in adult rat lung extract compared to prenatal or neonatal rat lung extracts. We conclude the lung contains developmentally regulated MnSOD mRNA-binding protein that is redox sensitive.
越来越明显的是，RNA结合蛋白在基因表达调控中发挥着重要作用。最近有报道称，在大鼠肺中存在一种特定的、对氧化还原敏感的过氧化氢酶RNA结合蛋白（Clerch, L. B., and D. Massaro, 1992. J. Biol. Chem. 267:2853）。为了确定是否存在特定的锰超氧化物歧化酶（MnSOD）RNA结合蛋白，我们测试了大鼠肺提取物中的蛋白质是否会与32P标记的MnSOD RNA结合。使用凝胶迁移率变动分析，我们发现大鼠肺蛋白与MnSOD RNA 3'非翻译区的一个216 b片段形成了特定的复合物，并且这种结合需要游离巯基的存在。竞争研究表明，MnSOD RNA结合蛋白与过氧化氢酶RNA结合蛋白不同。此外，与过氧化氢酶RNA结合蛋白不同，大鼠肺MnSOD RNA结合蛋白的活性受到发育调控；与产前或新生大鼠肺提取物相比，成年大鼠肺提取物中的MnSOD RNA-蛋白结合活性较低。我们得出结论，肺中含有受发育调控且对氧化还原敏感的MnSOD mRNA结合蛋白。
