Disrupted tRNA Gene Diversity and Possible Evolutionary Scenarios
Disrupted tRNA Gene Diversity and Possible Evolutionary Scenarios
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DOI：
10.1007/s00239-009-9294-6
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发表时间：
2009-11-01
影响因子：
3.9
通讯作者：
Kanai, Akio
中科院分区：
文献类型：
--
作者：
Sugahara, Junichi;Fujishima, Kosuke;Kanai, Akio
最近在古真核生物和原始真核生物的基因组中发现了以下不寻常的tRNA：含有多个内含子的tRNA，它有一个以上的内含子;分裂的tRNA，它是由两段RNA从不同的基因转录产生的;三分裂的tRNA，它是由三个不同的基因产生的;和排列的tRNA，其中50和30半在单个基因内以排列的方向编码。所有这些被破坏的tRNA基因可以形成成熟的连续tRNA，其在通过顺式或反式剪接加工后被氨酰化。这种tRNA中断的发现提出了一个问题，即这些复杂的tRNA加工途径在生命进化过程中何时以及为何出现。许多先前的报告指出，tRNA基因在反密码子环区域包含一个内含子，这是生命的所有三个领域都共有的特征，表明最后一个普遍共同祖先的古老特征。在这种情况下，这些独特的tRNA中断最近发现只有在古海洋和原始真核生物提供了新的见解tRNA基因的起源和进化，鼓励在这一领域的进一步研究。在本文中，我们总结了所有已知类型的中断的tRNA的发生，结构和加工机制，并讨论这些tRNA基因可能的进化方案。
The following unusual tRNAs have recently been discovered in the genomes of Archaea and primitive Eukaryota: multiple-intron-containing tRNAs, which have more than one intron; split tRNAs, which are produced from two pieces of RNA transcribed from separate genes; tri-split tRNAs, which are produced from three separate genes; and permuted tRNA, in which the 50 and 30 halves are encoded with permuted orientations within a single gene. All these disrupted tRNA genes can form mature contiguous tRNA, which is aminoacylated after processing by cis or trans splicing. The discovery of such tRNA disruptions has raised the question of when and why these complex tRNA processing pathways emerged during the evolution of life. Many previous reports have noted that tRNA genes contain a single intron in the anticodon loop region, a feature common throughout all three domains of life, suggesting an ancient trait of the last universal common ancestor. In this context, these unique tRNA disruptions recently found only in Archaea and primitive Eukaryota provide new insight into the origin and evolution of tRNA genes, encouraging further research in this field. In this paper, we summarize the phylogeny, structure, and processing machinery of all known types of disrupted tRNAs and discuss possible evolutionary scenarios for these tRNA genes.