A Study of New Arabidopsis Chloroplast RNA Editing Mutants Reveals General Features of Editing Factors and Their Target Sites
A Study of New Arabidopsis Chloroplast RNA Editing Mutants Reveals General Features of Editing Factors and Their Target Sites
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DOI：
10.1105/tpc.109.071472
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发表时间：
2009-11-01
期刊：
影响因子：
11.6
通讯作者：
Small, Ian
中科院分区：
文献类型：
--
作者：
Hammani, Kamel;Okuda, Kenji;Small, Ian
高等植物细胞器中的 RNA 编辑导致 RNA 中特定的胞苷残基转化为尿苷残基。编辑机制对特定目标 C 位点的识别涉及与待编辑 C 上游的 RNA 结合的反式作用因子。在过去几年中，对叶绿体生物发生中受影响的突变体的分析已经鉴定出来自 PLS 亚家族的几种五肽重复 (PPR) 蛋白，这些蛋白对于编辑特定 RNA 转录本至关重要。我们选择了来自同一亚科的其他基因，并使用反向遗传学方法鉴定了拟南芥中的六个新叶绿体编辑因子（OTP80、OTP81、OTP82、OTP84、OTP85 和 OTP86）。这六个因子解释了先前未分配给编辑因子的九个编辑位点，与先前描述的九个 PPR 编辑蛋白一起解释了拟南芥叶绿体中 34 个编辑事件的一半以上。 OTP80、OTP81、OTP85 和 OTP86 各自仅针对不同转录本中的一个编辑位点，OTP82 为两个位点，OTP84 为三个位点。对涉及多位点编辑的五个编辑因子（CRR22、CRR28、CLB19、OTP82 和 OTP84）的靶位点的分析表明，编辑因子通常可以区分嘧啶和嘌呤，并且在某些位置必须能够识别特定碱基。
RNA editing in higher plant organelles results in the conversion of specific cytidine residues to uridine residues in RNA. The recognition of a specific target C site by the editing machinery involves trans-acting factors that bind to the RNA upstream of the C to be edited. In the last few years, analysis of mutants affected in chloroplast biogenesis has identified several pentatricopeptide repeat (PPR) proteins from the PLS subfamily that are essential for the editing of particular RNA transcripts. We selected other genes from the same subfamily and used a reverse genetics approach to identify six new chloroplast editing factors in Arabidopsis thaliana (OTP80, OTP81, OTP82, OTP84, OTP85, and OTP86). These six factors account for nine editing sites not previously assigned to an editing factor and, together with the nine PPR editing proteins previously described, explain more than half of the 34 editing events in Arabidopsis chloroplasts. OTP80, OTP81, OTP85, and OTP86 target only one editing site each, OTP82 two sites, and OTP84 three sites in different transcripts. An analysis of the target sites requiring the five editing factors involved in editing of multiple sites (CRR22, CRR28, CLB19, OTP82, and OTP84) suggests that editing factors can generally distinguish pyrimidines from purines and, at some positions, must be able to recognize specific bases.