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Genetic System of Chloroplasts - Their Autonomy and Nuclear Dependency -

叶绿体遗传系统 - 它们的自主性和核依赖性 -

基本信息

批准号：
60480510
负责人：
OZEKI Haruo
金额：
$ 4.16万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-60480510/
关键词：
Liverwort Chloroplast DNA Entire DNA Sequence(121,024 bp)Universal Codons and 31 tRNAs Introns Prokaryotic Basic Machinery Gene Allocation 葉緑体の起源

项目摘要

Chloroplasts are geneticall controlled not only by their own genome but also by numerous nuclear genes. Nuclear encoded proteins are synthesized in cytoplasm as prcursors and then delivered into the organella. While the chloroplast genes are expressed within the chloroplasts via their own machinery for protein biogenesis, although the machinery itself is also composed partly of the nuclear gene products. As no RNA may be delivered from cytoplasm, all the necessary RNAs ought to be generated within the chloroplasts.To clarify the genetic share of chloroplast genome in plant cells, we have determined the entire chloroplast DNA sequence (121,024 bp) from a liverwort, Marchantia polymorpha, by using cultured green cells, and deduced the gene organization. We could detect 136 possible genes; i.e. 8 for two sets of rRNAs, 36 for 31 tRNA species, 91 for presumptive proteins or ORFs, and 1 for tRNA pseudogene. The universal codons are used throughout the genome and the 31 species of tRNA must … More translate them properly. Introns were detected in 20 genes, mostly of group <II> except one group <I> . About half of the chloroplast genes are concerned with the basic machinery for gene expression, including 9 rpl, 11 rps, 4 rpo, i infA and 44 RNA genes for rRNA and tRNA. These have been identified by comparing amino acid sequences with homologous genes in E. coli( resulting even in a similar order), showing a prokaryotic feature in the basic machinery. Ob-viously these genes are not enough to complete the transcription-translation machinery, and many remainder proteins must be supplied by the nuclear genes. Similarly, none of the protein complexes of photosynthetic and other apparatus are completed without nuclear encoded proteins. Since the allocation of each component in a complex to either chloroplast or nuclear genomes, which has been elucidated in liverwort, appears to be general among higher plants, the basis of present genetic system of chloroplasts in green plants has to be established before the blanching of Bryophytina and Tracheophytina, and from this unified single origin the present variety of chloroplast genomes in green plants may be evolved. Less

叶绿体不仅受其自身基因组的遗传控制，还受众多核基因的控制。核编码的蛋白质作为前体在细胞质中合成，然后输送到细胞器中。虽然叶绿体基因通过其自身的蛋白质生物合成机制在叶绿体内表达，但该机制本身也部分由核基因产物组成。由于细胞质中无法传递RNA，所有必需的RNA都应该在叶绿体中产生。为了阐明植物细胞中叶绿体基因组的遗传份额，我们利用培养的绿色细胞测定了地钱（地钱）的完整叶绿体DNA序列（121,024 bp），并推断了基因组织。我们可以检测到 136 个可能的基因；即 8 个用于两组 rRNA，36 个用于 31 个 tRNA 种类，91 个用于假定蛋白质或 ORF，1 个用于 tRNA 假基因。通用密码子用于整个基因组，31 种 tRNA 必须正确翻译它们。在20个基因中检测到内含子，除了一组<I>之外，大部分属于<II>组。大约一半的叶绿体基因与基因表达的基本机制有关，包括 9 rpl、11 rps、4 rpo、i infA 和 44 个 rRNA 和 tRNA 的 RNA 基因。这些是通过将氨基酸序列与大肠杆菌中的同源基因进行比较（甚至产生相似的顺序）来鉴定的，在基本机制中显示出原核特征。显然这些基因不足以完成转录-翻译机制，许多剩余蛋白质必须由核基因提供。同样，如果没有核编码的蛋白质，光合作用和其他装置的蛋白质复合物都是不完整的。由于在苔藓植物中已阐明的复合物中每个组分向叶绿体或核基因组的分配在高等植物中似乎是普遍的，因此在苔藓植物和气管植物变白之前必须建立绿色植物中现有叶绿体遗传系统的基础，并且从这个统一的单一起源可以进化出绿色植物中现有叶绿体基因组的多样性。较少的