Nelson James W, Breaker Ronald R
Department of Molecular, Cellular and Developmental Biology, Yale University, P.O. Box 208103, New Haven, CT 06520, USA.
Department of Molecular Biophysics and Biochemistry, Yale University, P.O. Box 208103, New Haven, CT 06520, USA.
Sci Signal. 2017 Jun 13;10(483):eaam8812. doi: 10.1126/scisignal.aam8812.
The possibility of an RNA World is based on the notion that life on Earth passed through a primitive phase without proteins, a time when all genomes and enzymes were composed of ribonucleic acids. Numerous apparent vestiges of this ancient RNA World remain today, including many nucleotide-derived coenzymes, self-processing ribozymes, metabolite-binding riboswitches, and even ribosomes. Many of the most common signaling molecules and second messengers used by modern organisms are also formed from RNA nucleotides or their precursors. For example, nucleotide derivatives such as cAMP, ppGpp, and ZTP, as well as the cyclic dinucleotides c-di-GMP and c-di-AMP, are intimately involved in signaling diverse physiological or metabolic changes in bacteria and other organisms. We describe the potential diversity of this "lost language" of the RNA World and speculate on whether additional components of this ancient communication machinery might remain hidden though still very much relevant to modern cells.
RNA世界的可能性基于这样一种观念，即地球上的生命曾经历过一个没有蛋白质的原始阶段，在那个时期，所有的基因组和酶都是由核糖核酸构成的。如今，这个古老的RNA世界仍留存着许多明显的遗迹，包括许多核苷酸衍生的辅酶、自我加工的核酶、代谢物结合核糖开关，甚至核糖体。现代生物体使用的许多最常见的信号分子和第二信使也是由RNA核苷酸或其前体形成的。例如，核苷酸衍生物如cAMP、ppGpp和ZTP，以及环二核苷酸c-di-GMP和c-di-AMP，都密切参与了细菌和其他生物体中各种生理或代谢变化的信号传递。我们描述了RNA世界这种“失落的语言”的潜在多样性，并推测这种古老通讯机制的其他组成部分是否可能仍然隐藏着，尽管它们与现代细胞仍然非常相关。
