TRANSFER OF RPL22 TO THE NUCLEUS GREATLY PRECEDED ITS LOSS FROM THE CHLOROPLAST AND INVOLVED THE GAIN OF AN INTRON
TRANSFER OF RPL22 TO THE NUCLEUS GREATLY PRECEDED ITS LOSS FROM THE CHLOROPLAST AND INVOLVED THE GAIN OF AN INTRON
复制标题
DOI：
10.1002/j.1460-2075.1991.tb07859.x
复制
发表时间：
1991-10-01
期刊：
影响因子：
11.4
通讯作者：
PALMER, JD
中科院分区：
文献类型：
--
作者：
GANTT, JS;BALDAUF, SL;PALMER, JD
大多数叶绿体和线粒体蛋白质由曾经存在于细胞器基因组中的核基因编码。这些基因中的大多数似乎在细胞器的内共生起源后不久就发生了转移，因此对这一过程知之甚少。我们努力了解叶绿体基因如何在功能上转移到核基因组中，这使我们发现了迄今为止描述的最新的进化基因转移。编码叶绿体核糖体蛋白CL 22的基因rpl 22存在于除豆科植物之外的所有植物的叶绿体基因组中，而rpl 22的功能性拷贝位于豆科豌豆的细胞核中。核rpl 22基因相对于其叶绿体祖先已经获得了两个额外的结构域：编码推定的N-末端转运肽的外显子，随后是将该第一外显子与该基因的进化上保守的叶绿体衍生部分分开的内含子。这种基因结构表明，转移区域可能已获得其转运肽的外显子改组的形式。令人惊讶的是，系统发育分析表明，rpl 22被转移到所有开花植物的共同祖先的细胞核中，至少在其从豆类叶绿体谱系中丢失之前1亿年。
Most chloroplast and mitochondrial proteins are encoded by nuclear genes that once resided in the organellar genomes. Transfer of most of these genes appears to have occurred soon after the endosymbiotic origin of organelles, and so little is known about the process. Our efforts to understand how chloroplast genes are functionally transferred to the nuclear genome have led us to discover the most recent evolutionary gene transfer yet described. The gene rpl22, encoding chloroplast ribosomal protein CL22, is present in the chloroplast genome of all plants examined except legumes, while a functional copy of rpl22 is located in the nucleus of the legume pea. The nuclear rpl22 gene has acquired two additional domains relative to its chloroplast ancestor: an exon encoding a putative N-terminal transit peptide, followed by an intron which separates this first exon from the evolutionarily conserved, chloroplast-derived portion of the gene. This gene structure suggests that the transferred region may have acquired its transit peptide by a form of exon shuffling. Surprisingly, phylogenetic analysis shows that rpl22 was transferred to the nucleus in a common ancestor of all flowering plants, at least 100 million years preceding its loss from the legume chloroplast lineage.