貪欲なプロモーターがマラリアの多様性をコントロールする
1Unité de Biologie des Interactions Hôte-Parasite CNRS-URA 2581, Institut Pasteur, Paris, France. ascherf@pasteur.fr
Cell
|January 28, 2006
まとめ
Plasmodium falciparumのようなマラリアの寄生虫は,相互排他的なvar遺伝子発現を用いて免疫を回避する. 新しい研究では,Varプロモーター構造が,この単一遺伝子の発現を強制することができ,免疫回避の重要なメカニズムであることが示されています.
科学分野:
- 寄生虫学とは,寄生虫学である.
- 免疫学 免疫学とは
- 分子生物学は分子生物学である.
背景:
- マラリアの寄生虫であるPlasmodium falciparumは,抗原変異と呼ばれるメカニズムを通じて宿主の免疫系を回避する.
- この変異は,寄生虫の表面タンパク質をコードするvar遺伝子ファミリーの遺伝子の相互排他的な発現に依存しています.
研究 の 目的:
- 転写的に活性なvarプロモーターが,Plasmodium falciparumの内生性var遺伝子のアレル排除を誘導するのに十分であるかどうかを調査する.
- マラリア寄生虫が採用する免疫回避戦略の基礎にある分子機構を理解する.
主な方法:
- 転写的に活性なヴァルプロモーターを含む遺伝子構造を用いた.
- プラズモディウム・ファルシパラムの寄生虫にこの構造を導入した.
- 改変した寄生虫における内生性Var遺伝子の発現パターンを分析した.
主要な成果:
- エンジニアリングされたコンストクトの存在が,単一の内生性変異遺伝子の相互排他的な発現を強制するのに十分であることを実証しました.
- varプロモーターが,アレル排除の調節に重要な役割を果たしていることを確認しました.
結論:
- 単一の転写的に活性なvarプロモーターは,内生性var遺伝子の相互排他的な発現を制御するのに十分です.
- この発見は,Plasmodium falciparumの免疫回避の分子基盤と介入のための潜在的なターゲットに関する重要な洞察を提供します.
関連する概念動画
02:02Cis-regulatory Sequences
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
02:40The Eukaryotic Promoter Region
The eukaryotic promoter region is a segment of DNA located upstream of a gene. It contains an RNA polymerase binding site, a transcription start site, and several cis-regulatory sequences. The proximal promoter region is located in the vicinity of the gene and has cis-regulatory sequences and the core promoter. The core promoter is the binding site for RNA polymerase and is usually located between -35 and +35 nucleotides from the transcription start site. The distal promoter regions are...
02:28Leaky Scanning
During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
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...
02:02Cis-regulatory Sequences
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
02:40The Eukaryotic Promoter Region
The eukaryotic promoter region is a segment of DNA located upstream of a gene. It contains an RNA polymerase binding site, a transcription start site, and several cis-regulatory sequences. The proximal promoter region is located in the vicinity of the gene and has cis-regulatory sequences and the core promoter. The core promoter is the binding site for RNA polymerase and is usually located between -35 and +35 nucleotides from the transcription start site. The distal promoter regions are...