AUU-TO-AUG MUTATION IN THE INITIATOR CODON OF THE TRANSLATION INITIATION-FACTOR IF3 ABOLISHES TRANSLATIONAL AUTOCONTROL OF ITS OWN GENE (INFC) INVIVO
AUU-TO-AUG MUTATION IN THE INITIATOR CODON OF THE TRANSLATION INITIATION-FACTOR IF3 ABOLISHES TRANSLATIONAL AUTOCONTROL OF ITS OWN GENE (INFC) INVIVO
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DOI：
10.1073/pnas.84.12.4022
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发表时间：
1987-06-01
影响因子：
11.1
通讯作者：
GRUNBERGMANAGO, M
中科院分区：
文献类型：
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作者：
BUTLER, JS;SPRINGER, M;GRUNBERGMANAGO, M
我们之前的研究表明，在体内，大肠杆菌翻译起始因子IF3在翻译水平上调控其自身基因infC的表达。在这里，我们在infC基因中创建了两个改变，并通过测量.beta来测试它们对体内infC表达的翻译自动控制的影响。-半乳糖苷酶活性在4倍抑制或3倍抑制infC表达的条件下由infC- lacz基因融合表达。用trp启动子替换infC启动子，在不影响自体翻译控制的情况下，将infC mRNA 5‘’的120个核苷酸删除到翻译起始位点。在体内，不寻常的AUU启动密码子突变为更常见的AUG启动密码子，可消除翻译启动因子if3依赖性的infC表达抑制和下调。这些结果证实了ifc的AUU启动子密码子是体内翻译起始因子IF3表达的自体翻译控制中必不可少的顺式作用元件。
We previously showed that Escherichia coli translation initiation factor IF3 regulates the expression of its own gene infC at the translational level in vivo. Here we create two alterations in the infC gene and test their effects on translational autocontrol of infC expression in vivo by measuring .beta.-galactosidase activity expressed from infC-lacZ gene fusions under conditions of up to 4-fold derepression or 3-fold repression of infC expression. Replacement of the infC promoter with the trp promoter deletes 120 nucleotides of the infC mRNA 5'' to the translation initiation site without affecting autogenous translational control. Mutation of the unusual AUU initiator codon of infC to the more common AUG initiator codon abolishes translation initiation factor IF3-dependent repression and derepression of infC expression in vivo. These results establish the AUU initiator codon of infC as an essential cis-acting element in autogenous translational control of translation initiation factor IF3 expression in vivo.