Lopes Raphael R S, Kessler Alan C, Polycarpo Carla, Alfonzo Juan D
Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Instituto de Bioquímica Médica Leopoldo de Meis, Programa de Biotecnologia e Biologia Molecular, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Wiley Interdiscip Rev RNA. 2015 May-Jun;6(3):337-49. doi: 10.1002/wrna.1279. Epub 2015 Mar 6.
All organisms encode transfer RNAs (tRNAs) that are synthesized as precursor molecules bearing extra sequences at their 5' and 3' ends; some tRNAs also contain introns, which are removed by splicing. Despite commonality in what the ultimate goal is (i.e., producing a mature tRNA), mechanistically, tRNA splicing differs between Bacteria and Archaea or Eukarya. The number and position of tRNA introns varies between organisms and even between different tRNAs within the same organism, suggesting a degree of plasticity in both the evolution and persistence of modern tRNA splicing systems. Here we will review recent findings that not only highlight nuances in splicing pathways but also provide potential reasons for the maintenance of introns in tRNA. Recently, connections between defects in the components of the tRNA splicing machinery and medically relevant phenotypes in humans have been reported. These differences will be discussed in terms of the importance of splicing for tRNA function and in a broader context on how tRNA splicing defects can often have unpredictable consequences.
所有生物体都编码转运RNA（tRNA），这些tRNA最初是以在其5'和3'末端带有额外序列的前体分子形式合成的；一些tRNA还含有内含子，这些内含子通过剪接被去除。尽管最终目标相同（即产生成熟的tRNA），但从机制上讲，细菌与古菌或真核生物之间的tRNA剪接存在差异。tRNA内含子的数量和位置在不同生物体之间甚至在同一生物体的不同tRNA之间都有所不同，这表明现代tRNA剪接系统在进化和持久性方面都具有一定程度的可塑性。在这里，我们将回顾最近的研究发现，这些发现不仅突出了剪接途径中的细微差别，还为tRNA中内含子的保留提供了潜在原因。最近，有报道称tRNA剪接机制成分的缺陷与人类医学相关表型之间存在联系。将从剪接对tRNA功能的重要性以及更广泛的背景下讨论这些差异，即tRNA剪接缺陷如何常常产生不可预测的后果。
