Novikova Olga, Belfort Marlene
Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222, USA.
Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222, USA; Department of Biomedical Sciences, School of Public Health, University at Albany, 1400 Washington Avenue, Albany, NY 12222, USA.
Trends Genet. 2017 Nov;33(11):773-783. doi: 10.1016/j.tig.2017.07.009. Epub 2017 Aug 14.
The duality of group II introns, capable of carrying out both self-splicing and retromobility reactions, is hypothesized to have played a profound role in the evolution of eukaryotes. These introns likely provided the framework for the emergence of eukaryotic retroelements, spliceosomal introns and other key components of the spliceosome. Group II introns are found in all three domains of life and are therefore considered to be exceptionally successful mobile genetic elements. Initially identified in organellar genomes, group II introns are found in bacteria, chloroplasts, and mitochondria of plants and fungi, but not in nuclear genomes. Although there is no doubt that prokaryotic and organellar group II introns are evolutionary related, there are remarkable differences in survival strategies between them. Furthermore, an evolutionary relationship of group II introns to eukaryotic retroelements, including telomeres, and spliceosomes is unmistakable.
II类内含子具有自我剪接和反转录移动反应的双重能力，据推测在真核生物的进化过程中发挥了深远的作用。这些内含子可能为真核生物反转录元件、剪接体内含子和剪接体的其他关键成分的出现提供了框架。II类内含子存在于生命的所有三个域中，因此被认为是极其成功的可移动遗传元件。II类内含子最初是在细胞器基因组中发现的，存在于植物和真菌的细菌、叶绿体和线粒体中，但不存在于核基因组中。尽管毫无疑问原核生物和细胞器II类内含子在进化上是相关的，但它们在生存策略上存在显著差异。此外，II类内含子与包括端粒在内的真核生物反转录元件和剪接体之间的进化关系是明确无误的。
