Kaberdina Anna Chao, Szaflarski Witold, Nierhaus Knud H, Moll Isabella
Max F. Perutz Laboratories, Department of Microbiology and Immunobiology, University Departments at the Vienna Biocenter, Vienna, Austria.
Mol Cell. 2009 Jan 30;33(2):227-36. doi: 10.1016/j.molcel.2008.12.014.
Translation of leaderless mRNAs, lacking ribosomal recruitment signals other than the 5'-terminal AUG-initiating codon, occurs in all three domains of life. Contemporary leaderless mRNAs may therefore be viewed as molecular fossils resembling ancestral mRNAs. Here, we analyzed the phenomenon of sustained translation of a leaderless mRNA in the presence of the antibiotic kasugamycin. Unexpected from the known in vitro effects of the drug, kasugamycin induced the formation of stable approximately 61S ribosomes in vivo, which were proficient in selectively translating leaderless mRNA. 61S particles are devoid of more than six proteins of the small subunit, including the functionally important proteins S1 and S12. The lack of these proteins could be reconciled with structural changes in the 16S rRNA. These studies provide in vivo evidence for the functionality of ribosomes devoid of multiple proteins and shed light on the evolutionary history of ribosomes.
缺乏除5'-末端AUG起始密码子之外的核糖体招募信号的无领导mRNA的翻译发生在生命的所有三个域中。因此,当代的无领导mRNA可以被视为类似于祖先mRNA的分子化石。在这里,我们分析了在抗生素春日霉素存在下无领导mRNA持续翻译的现象。与该药物已知的体外效应不同,春日霉素在体内诱导形成稳定的约61S核糖体,其能够选择性地翻译无领导mRNA。61S颗粒缺少小亚基的六种以上蛋白质,包括功能重要的蛋白质S1和S12。这些蛋白质的缺失可以与16S rRNA的结构变化相协调。这些研究为缺乏多种蛋白质的核糖体的功能提供了体内证据,并揭示了核糖体的进化历史。