Intron position as an evolutionary marker of thioredoxins and thioredoxin domains
Intron position as an evolutionary marker of thioredoxins and thioredoxin domains
复制标题
DOI：
10.1007/bf02498636
复制
发表时间：
1996-04
影响因子：
3.9
通讯作者：
M. Sahrawy;V. Hecht;J. López-Jaramillo;A. Chueca;Y. Chartier;Y. Meyer
中科院分区：
文献类型：
--
作者：
M. Sahrawy;V. Hecht;J. López-Jaramillo;A. Chueca;Y. Chartier;Y. Meyer
原核生物通常每个基因组具有一个硫氧还蛋白基因，与之相反，在高等植物中已经描述了三种不同的硫氧还蛋白类型。所有这些都是由核基因编码的，但硫氧还蛋白m和f是叶绿体的，而硫氧还蛋白h没有转运肽，可能是细胞质的。我们已经克隆并测序了拟南芥基因组片段编码的五个先前描述的硫氧还蛋白h，以及第六个基因编码一个新的硫氧还蛋白h。尽管序列的高度分歧，其中五个具有两个内含子的位置相同的先前测序的烟草硫氧还蛋白h基因，而一个只有第一个内含子。最近发表的衣原体硫氧还蛋白h序列显示了三个内含子，其中两个位于与高等植物相同的位置。这有力地表明了植物和绿色藻类的所有细胞质硫氧还蛋白的共同起源。此外，我们已经克隆和测序豌豆DNA基因组片段编码硫氧还蛋白m和f。硫氧还蛋白m序列显示在编码转运肽和成熟蛋白的区域之间只有一个内含子，支持该序列的原核起源，并表明其与转运肽的关联已通过外显子改组而得到促进。相比之下，硫氧还蛋白f序列显示两个内含子，一个位于与各种植物和动物硫氧还蛋白中的内含子相同的位置，第二个位于与二硫键异构酶的硫氧还蛋白结构域中的内含子相同的位置。这有力地支持了叶绿体硫氧还蛋白f起源于真核生物的假说。
In contrast to prokaryotes, which typically possess one thioredoxin gene per genome, three different thioredoxin types have been described in higher plants. All are encoded by nuclear genes, but thioredoxins m and f are chloroplastic while thioredoxins h have no transit peptide and are probably cytoplasmic. We have cloned and sequencedArabidopsis thalianagenomic fragments encoding the five previously described thioredoxins h, as well as a sixth gene encoding a new thioredoxin h. In spite of the high divergence of the sequences, five of them possess two introns at positions identical to the previously sequenced tobacco thioredoxin h gene, while a single one has only the first intron. The recently published sequence ofChlamydomonasthioredoxin h shows three introns, two at the same positions as in higher plants. This strongly suggests a common origin for all cytoplasmic thioredoxins of plants and green algae. In addition, we have cloned and sequenced pea DNA genomic fragments encoding thioredoxins m and f. The thioredoxin m sequence shows only one intron between the regions encoding the transit peptide and the mature protein, supporting the prokaryotic origin of this sequence and suggesting that its association with the transit peptide has been facilitated by exon shuffling. In contrast, the thioredoxin f sequence shows two introns, one at the same position as an intron in various plant and animal thioredoxins and the second at the same position as an intron in thioredoxin domains of disulfide isomerases. This strongly supports the hypothesis of a eukaryotic origin for chloroplastic thioredoxin f.