On the expansion of the pentatricopeptide repeat gene family in plants
On the expansion of the pentatricopeptide repeat gene family in plants
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DOI：
10.1093/molbev/msn057
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发表时间：
2008-06-01
影响因子：
10.7
通讯作者：
Small, Ian
中科院分区：
文献类型：
--
作者：
O'Toole, Nicholas;Hattori, Mitsuru;Small, Ian
五肽重复序列（PPR）蛋白在植物中形成了一个庞大的家族（拟南芥中有450个成员，水稻中有477个成员），由特征序列基序的串联重复定义。这些蛋白质中的一些已被证明在细胞器内的转录后过程中发挥作用，并且它们被认为是序列特异性RNA结合蛋白。这个家族的起源是模糊的，因为几乎所有的原核生物都缺乏它们，而这个家族在陆地植物中的惊人扩张也同样令人费解。在这项研究中，我们调查的家庭在植物中的增长进行全基因组识别和比较的PPR基因的3种生物：开花植物拟南芥和水稻和苔藓小立碗藓。在所有开花植物中，绝大多数PPR基因都是内含子较少的，而立碗藓属的103个PPR基因中，大多数都是内含子丰富的。PPR基因在所有3个物种的系统发育比较表明，富含内含子的PPR基因在立碗藓和一些内含子丰富的PPR基因在高等植物之间的相似性。所有3个物种中的内含子贫乏的PPR基因也显示出偏向于它们的内含子在它们的5'端的位置。这些结果提供了令人信服的证据，一个或多个波的反转录转座负责的开花植物的PPR基因家族的扩展。PPR蛋白的不同数量与3个物种之间细胞器RNA编辑的差异高度相关。
Pentatricopeptide repeat (PPR) proteins form a huge family in plants (450 members in Arabidopsis and 477 in rice) defined by tandem repetitions of characteristic sequence motifs. Some of these proteins have been shown to play a role in posttranscriptional processes within organelles, and they are thought to be sequence-specific RNA-binding proteins. The origins of this family are obscure as they are lacking from almost all prokaryotes, and the spectacular expansion of the family in land plants is equally enigmatic. In this study, we investigate the growth of the family in plants by undertaking a genome-wide identification and comparison of the PPR genes of 3 organisms: the flowering plants Arabidopsis thaliana and Oryza sativa and the moss Physcomitrella patens. A large majority of the PPR genes in each of the flowering plants are intron less. In contrast, most of the 103 PPR genes in Physcomitrella are intron rich. A phylogenetic comparison of the PPR genes in all 3 species shows similarities between the intron-rich PPR genes in Physcomitrella and the few intron-rich PPR genes in higher plants. Intron-poor PPR genes in all 3 species also display a bias toward a position of their introns at their 5' ends. These results provide compelling evidence that one or more waves of retrotransposition were responsible for the expansion of the PPR gene family in flowering plants. The differing numbers of PPR proteins are highly correlated with differences in organellar RNA editing between the 3 species.