期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1977
卷号：74
期号：7
页码：2692-2696
DOI：10.1073/pnas.74.7.2692
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We have compared the behavior of a prokaryotic mRNA in a eukaryotic ribosome binding system and of a eukaryotic mRNA in a prokaryotic ribosome binding system. Using 32P- and 125I-labeled bacteriophage f1 mRNA, we have shown that rabbit reticulocyte 80S ribosomes can protect specific sequences from pancreatic RNase digestion, including those sequences protected by Escherichia coli ribosomes. We have also found that E. coli ribosomes fail to protect any region of 125I-labeled globin mRNA. Iodination of the mRNA appeared to have little or no effect on the specificity of binding or protection by the ribosomes of either system. The eukaryotic and prokaryotic systems differ markedly in the ability of the small ribosomal subunits to protect mRNA from nuclease digestion. The regions of phage f1 mRNA protected by E. coli 30S subunits are virtually identical to those protected by the 70S ribosomes. By contrast, rabbit reticulocyte 40S subunits protect substantially larger fragments of mRNA from nuclease digestion than do the 80S ribosomes. These 40S-protected fragments are specific in the case of globin mRNA and overlap the shorter region protected by the 80S ribosomes. However, the 40S-protected fragments of phage f1 mRNA were found to be extremely heterogeneous, reflecting perhaps an important difference between the initial interactions made by these two mRNAs with the ribosomes.
关键词：ribosome binding ; protein synthesis ; 125I-labeled mRNA
