クロロプラストmRNAの編集は,初期コドンを作成することによって行われます
Nature
|September 12, 1991
まとめ
ミトコンドリアに共通するメッセンジャーRNA (mRNA) 編集は,植物クロロプラストでも起こります. 研究者らは,C-to-U塩基編集により,トウモロコシのクロロプラストmRNAのACGコドンをAUGスタートコドンに変換することを発見した.
科学分野:
- 植物分子生物学 植物分子生物学
- クロロプラストの遺伝子発現は
- RNAの編集メカニズム
背景:
- プライマリmRNAのトランスクリプトは,編集 (塩基置換,削除,挿入) を受けて,機能的なmRNAを形成します.
- ミトコンドリアのmRNAは,特に植物では,広範な編集が示されています.
- クロロプラストDNAでコードされたmRNAは,通常,明瞭なアミノ酸配列の予測を可能にしますが,時折,予想されたATGイニシエーションコドンではなく,ACGコドンが現れます.
研究 の 目的:
- クロロプラストにおけるRNA編集の発生とメカニズムを調査する.
- クロロプラスト遺伝子のACGからAUGのイニシアーションコドンへの変換にRNA編集が責任があるかどうかを判断する.
主な方法:
- トウモロコシプラストームからのrpl2遺伝子mRNAトランスクリプトの分析.
- mRNA配列における塩基変化の識別.
主要な成果:
- C-to-U ベース編集イベントの証拠が見つかりました.
- この編集は,rpl2 mRNAトランスクリプトのACGコドンをAUGイニシアチブコドンに変換します.
- クロロプラストにおけるRNA編集を実証した.
結論:
- RNA編集,特にCからUへの変換は,トウモロコシのクロロプラストで起こります.
- この編集メカニズムは,rpl2 mRNAのイニシアチブコドンを修正する.
- RNA編集はミトコンドリアに限ったものではありませんし,クロロプラストの遺伝子発現にも役割を果たします.
関連する概念動画
01:10Transcription
Overview
Transcription is the process of synthesizing RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. Additionally, many other proteins and regulatory sequences are involved in the proper synthesis of messenger RNA (mRNA). Regulation of transcription is responsible for the differentiation of all the different types of cells and often for the proper cellular response to environmental signals.
Transcription Can Produce Different Kinds...
Transcription is the process of synthesizing RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. Additionally, many other proteins and regulatory sequences are involved in the proper synthesis of messenger RNA (mRNA). Regulation of transcription is responsible for the differentiation of all the different types of cells and often for the proper cellular response to environmental signals.
Transcription Can Produce Different Kinds...
02:01pre-mRNA Processing
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
02:36Transfer RNA Synthesis
One of the unique features of tRNA is the presence of modified bases. In some tRNAs, modified bases account for nearly 20% of the total bases in the molecule. Altogether, these unusual bases protect the tRNA from enzymatic degradation by RNases.
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
02:23RNA Editing
RNA editing is a post-transcriptional modification where a precursor mRNA (pre-mRNA) nucleotide sequence is changed by base insertion, deletion, or modification. The extent of RNA editing varies from a few hundred bases, in mitochondrial DNA of trypanosomes, to a just single base, in nuclear genes of mammals. Even a single base change in the pre-mRNA can convert a codon for one amino acid into the codon for another amino acid or a stop codon. This type of re-coding can significantly affect the...
01:17Transcription
Transcription is the synthesis of RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. Additionally, many other proteins and regulatory sequences are involved in correctly synthesizing messenger RNA (mRNA). Transcriptional regulation is responsible for the differentiation of different types of cells and often for the proper cellular response to environmental signals.
Transcription Can Produce Different Kinds of RNA Molecules
In eukaryotes,...
Transcription Can Produce Different Kinds of RNA Molecules
In eukaryotes,...
02:36Transfer RNA Synthesis
One of the unique features of tRNA is the presence of modified bases. In some tRNAs, modified bases account for nearly 20% of the total bases in the molecule. Altogether, these unusual bases protect the tRNA from enzymatic degradation by RNases.
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...