高等植物细胞器Ⅱ类内含子剪接的研究进展

Research progress of group Ⅱ intron splicing in higher plant organelles

Ⅱ类内含子是一类自我剪接内含子,存在于真菌、细菌及古细菌中,在植物细胞器中尤为普遍。典型Ⅱ类内含子的剪接与剪接体内含子类似,由内含子RNA及其编码的成熟酶介导完成。高等植物细胞器中,Ⅱ类内含子成熟酶的结构发生变异,导致自剪接功能丧失,需要核编码蛋白因子辅助完成其剪接过程。自第一个参与叶绿体Ⅱ类内含子剪接的核编码蛋白被发现以来,越来越多的参与高等植物细胞器Ⅱ类内含子剪接的核编码蛋白因子被报道。本文就高等植物细胞器Ⅱ类内含子的分布、结构、剪接方式,尤其参与它们剪接的核编码蛋白因子作一综述。

Group Ⅱ introns are large self-spliced introns that are found in fungi, bacteria and archaebacteria, but are particularly prevalent within the organelle genomes in plants. The splicing of typical group Ⅱ introns is closely resembles to that of the nuclear spliceosomal introns, which is carried out by the complex of intron RNA and intron-encoded maturase. However, group Ⅱ introns in higher plant organelles have lost the ability to self-splice in vivo and require nucleus-encoded proteins as cofactors. Since the first splicing factor was identified in chloroplasts, more and more nuclear-encoded proteins have been shown to be involved in the splicing of the introns in chloroplasts or mitochondria. In this review, we will summarize the data on the distribution, structure and splicing of group Ⅱ introns in higher plant organelles, with a focus on their nuclear-encoded splicing cofactors.