Enhancement of+1 frameshift by polyamines during translation of polypeptide release factor 2 in Escherichia coli
Enhancement of+1 frameshift by polyamines during translation of polypeptide release factor 2 in Escherichia coli
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DOI：
10.1074/jbc.m513752200
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发表时间：
2006-04-07
影响因子：
4.8
通讯作者：
Igarashi, K
中科院分区：
文献类型：
--
作者：
Higashi, K;Kashiwagi, K;Igarashi, K
已知大肠杆菌中的多肽释放因子2（RF 2）通过RF 2 mRNA的第26位UGA密码子的+1移码来合成。多胺被发现刺激RF 2合成的+1移码，这种作用被过量的RF 2所减少。在对数期早期观察到多胺刺激RF 2合成的+1移码，对数期是确定细胞生长总体速率的重要阶段。Shine-Dalgarno样序列对于RF 2合成的有效+1移码是必需的，但对于多胺刺激不是必需的。大观霉素、四环素、链霉素和新霉素减少了多胺对RF 2合成+1移码的刺激。结果表明，30 S核糖体亚基上的A位点的结构变化是重要的多胺刺激+1移码。核糖体蛋白质和延伸因子的mRNA的水平具有UAA作为终止密码子的多胺的增强，和OppA合成从OppA mRNA具有UAA作为终止密码子的多胺比从OppA mRNA具有UGA终止密码子的多胺的增强。此外，核糖体蛋白L20和延伸因子G的合成从剃一个UAA终止密码子的mRNA的增强多胺在翻译和转录水平。结果表明，一些蛋白质合成的mRNA具有UAA终止密码子的增强翻译水平，通过多胺刺激+1移码的RF 2合成。因此，prfB基因编码的RF 2是多胺调节子的一个新成员。
Polypeptide release factor 2 (RF2) in Escherichia coli is known to be synthesized by a +1 frameshift at the 26th UGA codon of RF2 mRNA. Polyamines were found to stimulate the +1 frameshift of RF2 synthesis, an effect that was reduced by excess RF2. Polyamine stimulation of +1 frameshift of RF2 synthesis was observed at the early logarithmic phase, which is the important phase in determination of the overall rate of cell growth. A Shine-Dalgarno-like sequence was necessary for an efficient +1 frameshift of RF2 synthesis, but not for polyamine stimulation. Spectinomycin, tetracycline, streptomycin, and neomycin reduced polyamine stimulation of the +1 frameshift of RF2 synthesis. The results suggest that a structural change of the A site on 30 S ribosomal subunits is important for polyamine stimulation of the +1 frameshift. The level of mRNAs of ribosomal proteins and elongation factors having UAA as termination codon was enhanced by polyamines, and OppA synthesis from OppA mRNA having UAA as termination codon was more enhanced by polyamines than that from OppA mRNA having a UGA termination codon. Furthermore, synthesis of ribosomal protein L20 and elongation factor G from the mRNA shaving a UAA termination codon was enhanced by polyamines at the level of translation and transcription. The results suggest that some protein synthesis from mRNAs having a UAA termination codon is enhanced at the level of translation through polyamine stimulation of +1 frameshift of RF2 synthesis. It is concluded that prfB encoding RF2 is a new member of the polyamine modulon.