カリフラワーモザイクウイルスのポストトランスクリプショントランス活性化
J M Bonneville1, H Sanfaçon, J Fütterer
1Friedrich Miescher-Institut, Basel, Switzerland.
Cell
|December 22, 1989
まとめ
植物細胞は,カリフラワーモザイクウイルスからのディシストロニックmRNAを翻訳することができます. ウイルスのORF VIによるトランス活性化は,これらのウイルスのmRNAsのダウンストリーム遺伝子発現を強化します.
科学分野:
- 植物分子生物学 植物分子生物学
- ウイルス学 ウイルス学 ウイルス学
- 遺伝子発現の表現について
背景:
- カリフラワーモザイクウイルス (CaMV) は,ポリシストロニックRNAを産生し,標準的な翻訳機構に挑戦します.
- 植物細胞がウイルスのポリシストロニックmRNAをどのように処理するかを理解することは,ウイルスの遺伝子発現の研究にとって極めて重要です.
研究 の 目的:
- 植物細胞におけるディシストロニックmRNAの翻訳を調査する.
- ポリシストロニックmRNAのダウンストリーム遺伝子発現を調節するカフリフラワーモザイクウイルス (CaMV) 遺伝子VIの役割を決定する.
主な方法:
- クロランフェニコルアセチルトランスフェラーゼ (CAT) とベータグルキュロニダゼ (GUS) のレポーター遺伝子をCaMV ORF I.に融合させ,ディシストロニックmRNAを構成する.
- 植物原形質をレポータープラズミドとCaMVDNAで変異させる.
- トランス活性化遺伝子 (ORF VI) のデレーション解析を行う.
主要な成果:
- レポーター遺伝子発現は,ウイルスのDNAと共伝染された場合にのみ有意に増加し,トランス活性化メカニズムを示した.
- トランスアクティベーションは,上流ORF発現に影響を与えることなく,下流レポーター遺伝子の発現を特に促進しました.
- 主要レポーターのトランスクリプトはバイシストロニックであり,トランス活性化時に豊富な変化が限られている.
結論:
- CaMV ORF VIは,ポリシストロニックmRNAのダウンストリームオープンリーディングフレーム (ORF) の翻訳をトランス活性化します.
- このトランス活性化メカニズムは,ウイルスRNAの文脈内の下流遺伝子発現の効率を高めます.
- この発見は,植物ウイルスが採用する複雑な転写後の調節戦略に光を当てています.
関連する概念動画
02:36RNA Polymerase II Accessory Proteins
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
02:42Eukaryotic Transcription Activators
Transcription activators are proteins that promote the transcription of genes from DNA to RNA. In most cases, these proteins contain two separate domains ‒ a domain that binds to DNA and a domain for activating transcription; however, in some cases, a single domain is responsible for both binding and activation of transcription, as seen in the glucocorticoid receptor and MyoD.
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
02:50Transgenic Plants
Recombinant DNA technology called transgenesis is often used to add a foreign gene or remove a detrimental gene from an organism. Such genetically modified organisms are called transgenic organisms.
The first-ever transgenic plant was a tobacco plant developed in 1983 that showed resistance against the tobacco mosaic virus. Since then, many transgenic plants have been developed and commercialized for improving the agricultural, ornamental, and horticultural value of a crop plant. Transgenic...
The first-ever transgenic plant was a tobacco plant developed in 1983 that showed resistance against the tobacco mosaic virus. Since then, many transgenic plants have been developed and commercialized for improving the agricultural, ornamental, and horticultural value of a crop plant. Transgenic...
01:51Mechanisms of Retrovirus-induced Cancers
Retroviruses are RNA viruses that have been shown to cause cancers in diverse species, including chickens, mice, cats, and monkeys. The RNA genomes of these viruses are first reverse-transcribed into single and then double-stranded DNA (dsDNA) copies. This dsDNA called proviral DNA then integrates into the host genome. Subsequently, the host cell transcribes the proviral DNA in concert with the chromosomal DNA. This leads to the production of viral RNA and proteins that assemble at the host...
02:26tRNA Activation
Aminoacyl-tRNA synthetases are present in both eukaryotes and bacteria. Though eukaryotes have 20 different aminoacyl-tRNA synthetases to couple to 20 amino acids, many bacteria do not have genes for all of these aminoacyl-tRNA synthetases. Despite this, they still use all 20 amino acids to synthesize their proteins. For instance, some bacteria do not have the gene encoding the enzyme that couples glutamine with its partner tRNA. In these organisms, one enzyme adds glutamic acid to all of the...
01:24Transposons
Transposons, or "jumping genes," are small mobile genetic elements (MGEs) that range from 700 to 40,000 base pairs in length. They are found in all organisms and can move within the same chromosome or transfer to different chromosomes. In some cases, transposons can also jump between different host DNA molecules, such as plasmids or viruses, contributing to genetic variability.Barbara McClintock first discovered these mobile genetic elements in the 1940s while studying maize genetics, and she...