AtnMat2, a nuclear-encoded maturase required for splicing of group-II introns in Arabidopsis mitochondria
AtnMat2, a nuclear-encoded maturase required for splicing of group-II introns in Arabidopsis mitochondria
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DOI：
10.1261/rna.1776409
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发表时间：
2009-12-01
期刊：
影响因子：
4.5
通讯作者：
Ostersetzer-Biran, Oren
中科院分区：
文献类型：
--
作者：
Keren, Ido;Bezawork-Geleta, Ayenachew;Ostersetzer-Biran, Oren
植物线粒体（mt）中含有约20个II组内含子，它们位于细胞器基因组表达和呼吸活动所需的蛋白质编码基因内。虽然在非植物系统中，II组内含子的剪接是由内含子本身编码的蛋白质（称为“成熟酶”）介导的，但在植物的线粒体基因组中仅保留了单一的成熟酶ORF（matR）;然而，其在细胞器内含子剪接中的假定作用尚未确定。其他蛋白质的线索是稀缺的，但这些可能是在细胞核内编码的，因为在线粒体DNA内的剩余ORF中没有明显的候选者。有趣的是，高等植物基因组中包含四个成熟酶相关基因，它们以独立的ORF形式存在于细胞核中，脱离了与进化相关的第二组内含子的宿主环境。这些都被预测存在于线粒体内，因此可能在细胞器编码内含子的剪接中起反式作用。在这里，我们分析了细胞内的位置的四个核编码的成熟酶在拟南芥中，并建立了这些基因之一，At 5g 46920（AtnMat 2），在剪接的几个线粒体内含子，包括cox 2，nad 1内含子2和nad 7内含子2内的单个内含子的作用。
Mitochondria (mt) in plants house about 20 group-II introns, which lie within protein-coding genes required in both organellar genome expression and respiration activities. While in nonplant systems the splicing of group-II introns is mediated by proteins encoded within the introns themselves (known as "maturases''), only a single maturase ORF (matR) has retained in the mitochondrial genomes in plants; however, its putative role(s) in the splicing of organellar introns is yet to be established. Clues to other proteins are scarce, but these are likely encoded within the nucleus as there are no obvious candidates among the remaining ORFs within the mtDNA. Intriguingly, higher plants genomes contain four maturase-related genes, which exist in the nucleus as self-standing ORFs, out of the context of their evolutionary-related group-II introns "hosts.'' These are all predicted to reside within mitochondria and may therefore act "in-trans'' in the splicing of organellar-encoded introns. Here, we analyzed the intracellular locations of the four nuclear-encoded maturases in Arabidopsis and established the roles of one of these genes, At5g46920 (AtnMat2), in the splicing of several mitochondrial introns, including the single intron within cox2, nad1 intron2, and nad7 intron2.