Molecular genetic study on gene expression in chloroplasts.

叶绿体基因表达的分子遗传学研究。

基本信息

批准号：
62480001
负责人：
OZEKI Haruo
金额：
$ 4.22万
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：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

Chloroplast genes are expressed within the prganelles via their own machinery for prttein biogenesis, although the machinery itself is composed not only of their own gene products but also of the nuclear gene products. We have determined the entire DNA sequence of liverwort chloroplast genome and deduced 127 distinct genes. About half of them are concerned with the basic mechanisms of gene expression in the chloroplasts, such as transcription and translation, and share many features with prokaryotic organisms. Chloroplast ribosomes are prokaryotic 70S, and genetic signals such as promotors, terminatews, SD-sequences etc. are also bacteria types. Thus the genetic system of chloroplasts is basically prokaryotic, supporting the hypothesis of endosymbiotic origin of bacteria. On the other hand, however, many chloroplast genes are interruped by introns(catalytic ones of hroup I or II), differring from bacteria, and thus require post-transcriptional RNA splicing for their gene expression. Analysis of chloroplast RNAs prepared from cultured liverwort cells showed that the primary RNA transcripts usually contained poly-cistronic messages which were then processed into smaller mRNAs prior to splicing. If a gene contained two introns, the splicing proceeded successively from the 5' to 3' direction. We also proposed a bimolecular interaction model for trans-splicing. In conclusion, we postulated matulation pathways for mRNAs in chloroplasts from the primary RNA transcripts via RNA processing and splicing cis and trans.

叶绿体基因通过其自身的prttein生物发生机制在prganelles中表达，尽管该机械本身不仅由其自己的基因产物，而且由核基因产物组成。我们已经确定了叶绿体基因组的整个DNA序列，并推断了127个不同的基因。其中大约一半涉及叶绿体中基因表达的基本机制，例如转录和翻译，并与原核生物具有许多特征。叶绿体核糖体是原核生物70，遗传信号，例如启动子，终止，SD序列等也是细菌类型。因此，叶绿体的遗传系统基本上是原核生物，支持细菌内共生生物的假设。但是，另一方面，许多叶绿体基因被内含子（Hroup I或II的催化催化剂）关节，与细菌不同，因此需要转录后RNA剪接其基因表达。从培养的肝脏细胞制备的叶绿体RNA分析表明，主要的RNA转录本通常包含聚发信息，然后在剪接之前将其处理成较小的mRNA。如果一个基因包含两个内含子，则剪接从5“到3”方向连续进行。我们还提出了一个双分子相互作用模型，用于移媒体。总之，我们假设通过RNA处理和剪接顺式和反式从原代RNA转录本中的叶绿体中mRNA的模拟途径。