In vitro進化は,ハンマーヘッドリボジームの複数の起源を示唆しています
K Salehi-Ashtiani1, J W Szostak
1Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston 02114, USA.
Nature
|November 2, 2001
まとめ
ハンマーヘッドリボ酵素は,自己分裂RNAモチーフであり,生理学的条件下で自己分裂RNAのための最もシンプルで最も一般的な構造です. これは,生物化学の問題に対する最も単純な解決策を進化が好むことを示唆し,その広範な発生を説明しています.
科学分野:
- 分子生物学は分子生物学である.
- 進化生物学の進化生物学について
- バイオケミストリー バイオケミストリー
背景:
- ハンマーヘッドリボ酵素は,植物,ニート,シストソーム,洞窟クリケットなど,様々な生物に見られる自己分裂RNAモチーフです.
- その散発的な分布は,古代の起源か,異なる種間の独立した進化のいずれかを示唆しています.
- リボジームの分布を形作る進化的圧力を理解することは極めて重要です.
研究 の 目的:
- ハンマーヘッドリボ酵素の進化的起源と分布を調査する.
- 生物学的に重要な速度で自己分裂できる最も単純なRNA構造を決定する.
- 進化の過程が,生化学的機能の単純な解決策を好むかどうかを調査する.
主な方法:
- ランダムなRNA配列の偏らないライブラリをスクリーニングするために,インビトロ選択が採用されました.
- 選択の目的は,既知のハンマーヘッドリボ酵素に匹敵する活性を持つ自己分裂モチーフを特定することでした.
- 実験は,生物学的環境を模倣するために,ほぼ生理学的条件下で実施されました.
主要な成果:
- ハンマーヘッドリボエンザイムモチーフは,自己分裂を可能にする最も一般的な,最も単純なRNA構造として現れた.
- この自己分裂は,生物系で観察されたものと同等の速さで発生した.
- 発見は,ほぼ生理学的条件を超えて一貫していました.
結論:
- ハンマーヘッドリボ酵素の流行は,進化の経路がしばしば最も単純な生化学的解決へと導かれていることを示唆しています.
- 最も単純な機能的構造を選択するこの原理は,自然界でその広範な発生を説明するかもしれない.
- 実験室での選択は,単純性を好む自然の進化過程を反映しています.
関連する概念動画
00:43Bacterial RNA Polymerase
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
02:47Ribozymes
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can be...
Ribozymes can be...
02:32Exon Recombination
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Exon shuffling follows “splice frame rules.” Each exon has three reading...
02:47Ribozymes
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can be...
Ribozymes can be...
01:24Eukaryotic Evolution
The endosymbiont theory is the most widely accepted theory of eukaryotic evolution; however, its progression is still somewhat debated. According to the nucleus-first hypothesis, the ancestral prokaryote first evolved a membrane to enclose DNA and form the nucleus. Conversely, the mitochondria-first hypothesis suggests that the nucleus was formed after endosymbiosis of mitochondria.
Contrary to the endosymbiont theory, the eukaryote-first hypothesis proposes that the simpler prokaryotic and...
Contrary to the endosymbiont theory, the eukaryote-first hypothesis proposes that the simpler prokaryotic and...
00:43Bacterial RNA Polymerase
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...