CHLOROPLAST GENE ORGANIZATION DEDUCED FROM COMPLETE SEQUENCE OF LIVERWORT MARCHANTIA-POLYMORPHA CHLOROPLAST DNA
CHLOROPLAST GENE ORGANIZATION DEDUCED FROM COMPLETE SEQUENCE OF LIVERWORT MARCHANTIA-POLYMORPHA CHLOROPLAST DNA
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DOI：
10.1038/322572a0
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发表时间：
1986-08-07
期刊：
影响因子：
64.8
通讯作者：
OZEKI, H
中科院分区：
文献类型：
--
作者：
OHYAMA, K;FUKUZAWA, H;OZEKI, H
叶绿体含有自己自主复制的DNA基因组。叶绿体中存在的大部分蛋白质是由核DNA编码的，但其余的蛋白质是由叶绿体DNA编码的，并由叶绿体转录-翻译机制1-4合成。尽管来自不同植物的许多叶绿体基因的核苷酸序列已经确定，但尚未有任何植物的叶绿体基因组的完整基因组织被阐明。为了加深对叶绿体基因系统的了解，我们测定了多形地钱的叶绿体DNA的全序列，并推测了其基因组织。据报道，地钱属植物叶绿体DNA包含121,024个碱基对，由一组大的反向重复序列(IRA和IRB，每个10,058个碱基)组成，由一个小的单复制区(SSC，19,813个碱基对)和一个大的单复制区(LSC，81,095个碱基对)分隔。我们在地钱植物叶绿体基因组中检测到128个可能的基因，包括4种核糖体RNAs的编码序列，32种转移RNAs和55个已鉴定的蛋白质开放阅读框架(ORF)，它们之间有短的A+T-富间隔区(图1)。20个基因(8个编码tRNA，12个编码蛋白质)在其编码序列中含有内含子。这些内含子可以被归类为属于组I或组II，如线粒体5所述。有趣的是，已鉴定的7个ORF与在人类线粒体6，7中发现的未鉴定阅读框架(URF)高度同源。
Chloroplasts contain their own autonomously replicating DNA genome. The majority of proteins present in the chloroplasts are encoded by nuclear DNA, but the rest are encoded by chloroplast DNA and synthesized by the chloroplast transcription–translation machinery1–4. Although the nucleotide sequences of many chloroplast genes from various plant species have been determined, the entire gene organization of the chloroplast genome has not yet been elucidated for any species of plants. To improve our understanding of the chloroplast gene system, we have determined the complete sequence of the chloroplast DNA from a liverwort,Marchantia polymorpha, and deduced the gene organization. As reported here the liverwort chloroplast DNA contains 121,024 base pairs (bp), consisting of a set of large inverted repeats (IRAand IRB, each of 10,058 bp) separated by a small single-copy region (SSC, 19,813 bp) and a large single-copy region (LSC, 81,095 bp). We detected 128 possible genes throughout the liverwort chloroplast genome, including coding sequences for four kinds of ribosomal RNAs, 32 species of transfer RNAs and 55 identified open reading frames (ORFs) for proteins, which are separated by short A+T-rich spacers (Fig. 1). Twenty genes (8 encoding tRNAs, 12 encoding proteins) contain introns in their coding sequences. These introns can be classified as belonging to either group I or group II, as described for mitochondria5. Interestingly, seven of the identified ORFs show high homology to unidentified reading frames (URFs) found in human mitochondria6,7.