《生命科学》 2009, 21(4): 524-530
摘 要：摘 要：自我剪接内含子是指具有催化活性的RNA分子，可介导自身的剪切和两侧外显子的连接。自我剪接内含子包括Ⅰ型内含子和Ⅱ型内含子两类，主要存在于原生生物、真菌、藻类、植物细胞器以及细菌和古细菌(Ⅱ型内含子)基因组中。尽管核苷酸序列保守性很低，但两类自我剪接内含子均能分别形成不同的保守二级结构，且它们都可通过两步连续的转酯反应完成剪接。但由于其结构存在较大差异，导致其剪接机制也各不相同。对其结构与剪接关系的深入研究将有助于进一步探索自我剪接内含子在生物体内的功能、起源和进化。
关键词：自我剪接内含子; ORF; 结构; 剪接; 成熟酶
Abstract: Abstract: Self-splicing introns are catalytic RNAs and divided into two groups， group I intron and group II intron. They are found in mitochondria and chloroplasts genomes of plants， fungi， protists and algae， as well as in bacterial and archaebacterial (group II intron) genomes. All self-splicing introns can fold into their respective conserved secondary structures， although they are different in sequences. The typical secondary structure of a group I intron consists of approximately ten paired elements， and group Ⅱ introns have a typical structure with six double-helical domains (DI- DVI). Self-splicing introns can self-splice from their pre-RNAs by two consecutive transesterification reactions joining the flanking exons and releasing the introns. Group I introns use an exogenous G to initiate the splicing reaction， but group II introns use an internal bulged adenosine in DVI. Their respective secondary structure and protein factors are all important for the splicing reaction. Group I intron and group II intron have been used in bioengineering and also have many potential applications in functional genome and gene therapy. Self-splicing introns have become a research focus with the development of their structure and function.
Key words: self-splicing introns; ORF; structure; splicing; maturase
