miRNAは,単細胞藻であるクラミドモナス・ラインハーディティ (Chlamydomonas reinhardtii) の遺伝子発現を制御する
Attila Molnár1, Frank Schwach, David J Studholme
1Sainsbury Laboratory, John Innes Centre, Norwich NR4 7UH, UK.
Nature
|June 1, 2007
まとめ
この研究では,クロミドモナス・ラインハーディ (Chlamydomonas reinhardtii) という藻類のマイクロRNA (miRNA) と小さな干渉RNA (siRNA) が検出されました. これらの発見は,複雑なRNAサイレンシングが,原始的な真核細胞の多細胞性以前に進化したことを示唆しています.
科学分野:
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
- 進化生物学の進化生物学について
背景:
- マイクロRNA (miRNA) と小干渉RNA (siRNA) は,真核生物における遺伝子発現の重要な調節因子である.
- これらのRNA分子はDicerヌクレアゼによって処理され,アルゴナウトを含む複合体内で機能します.
- 以前は,miRNAは多細胞性で進化したと考えられ,単細胞生物には存在しないと考えられていた.
研究 の 目的:
- 単細胞藻クロミドモナス・ラインハーディ (Chlamydomonas reinhardtii) の小さなRNAの存在と機能を調査する.
- miRNAとsiRNA経路の進化的起源を探求する.
- RNAサイレンシングシステムが多細胞性以前のものであるかどうかを判断する.
主な方法:
- Chlamydomonas reinhardtiiからの小さなRNA配列のバイオインフォマティック分析.
- miRNAとsiRNAの前駆体および成熟した分子の識別と特徴付け.
- 植物や動物の既知のRNAサイレンシング経路との比較分析.
主要な成果:
- クラミドモナスの miRNAsと推定 miRNA 前駆体の発見 reinhardtii.
- 高級植物に見られるものと類似した siRNA 種の特定.
- Chlamydomonas reinhardtiiは,機能的なRNAサイレンシング機構を有しています.
結論:
- 単細胞藻にmiRNAsとsiRNAsの両方の存在は,miRNAsが多細胞性によってのみ進化したという概念に異議を唱える.
- miRNA経路を含む複雑なRNAサイレンシングシステムは,植物と動物の系統が分岐する前の初期の真核細胞に起源を持つ可能性が高い.
- この研究は,RNA媒介の遺伝子調節の古代の進化的起源の証拠を提供します.
関連する概念動画
01:22MicroRNAs
MicroRNA (miRNA) are short, regulatory RNA transcribed from introns—non-coding regions of a gene—or intergenic regions—stretches of DNA present between genes. Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA ends...
02:15Experimental RNAi
RNA interference (RNAi) is a cellular mechanism that inhibits gene expression by suppressing its transcription or activating the RNA degradation process. The mechanism was discovered by Andrew Fire and Craig Mello in 1998 in plants. Today, it is observed in almost all eukaryotes, including protozoa, flies, nematodes, insects, parasites, and mammals. This precise cellular mechanism of gene silencing has been developed into a technique that provides an efficient way to identify and determine the...
02:11Reporter Genes
Reporter genes are a type of protein-coding gene that are often tagged to a gene of interest. Once inside a target cell, reporter genes usually produce visually identifiable characteristics like fluorescence and luminescence when expressed along with the gene of interest. Thus, reporter genes “report” the presence or absence of genes of interest in an organism, determine the gene expression pattern, or track the physical location of a DNA segment or protein in the cell.
Commonly used reporter...
Commonly used reporter...
01:11Channel Rhodopsins
Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
01:22MicroRNAs
MicroRNA (miRNA) are short, regulatory RNA transcribed from introns (non-coding regions of a gene) or intergenic regions (stretches of DNA present between genes). Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself, forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA...
01:23Regulation of Expression at Multiple Steps
The gene expression in cells is regulated at different stages: (i) transcription, (ii) RNA processing, (iii) RNA localization, and (iv) translation. Transcriptional regulation is mediated by regulatory proteins such as transcription factors, activators, or repressors—these control gene expression by initiating or inhibiting the transcription of genes. Once a precursor or pre-mRNA is produced, it undergoes post-transcriptional modification, including 5' capping, splicing, and the addition of a...