2026-01-29 マックス・プランク研究所
ドイツのマックス・プランク研究所の研究チームは、褐藻類が生活環の重要な転換点、すなわち栄養成長から性成熟への移行や次世代を担う細胞の決定をたった1種類のARGONAUTE(AGO)タンパク質で制御していることを発見した。通常、植物や動物ではAGOタンパク質ファミリーが複数の役割を担うが、褐藻類は1つのAGOタンパク質と小さなRNA分子の組み合わせで精密な遺伝子発現制御を実現している。研究では、この単一のAGOが配偶体形成や生殖系列の確立に不可欠であることが示され、遺伝子スイッチとして機能するシンプルなメカニズムが明らかになった。これにより、進化過程で複雑な分子系が必ずしも必要でない可能性や、小さなRNAによる軽量な制御システムの存在が示唆される。褐藻という比較的単純な多細胞生物が、最小限の分子セットで高度な発生制御を行う例として、生命の発生・進化制御の理解に新たな視点を提供する。
<関連情報>
- https://www.mpg.de/26050712/one-single-protein-for-sexual-development
- https://www.pnas.org/doi/10.1073/pnas.2518712123
エクトカルプスにおける単一のARGONAUTEタンパク質による生殖細胞運命決定 Germline fate determination by a single ARGONAUTE protein in Ectocarpus
Viktoriia Bukhanets, Rita A. Batista, Fabian B. Haas, +6 , and Susana M. Coelho
Proceedings of the National Academy of Sciences Published:January 28, 2026
DOI:https://doi.org/10.1073/pnas.2518712123
Significance
ARGONAUTE (AGO) proteins are central regulators of gene expression in multicellular eukaryotes, mediating developmental processes through interactions with small RNAs. While extensively studied in plants and animals, the diversity of AGO function across independently evolved multicellular lineages remains poorly understood. Using brown algae as a comparative model, we demonstrate that a single AGO protein can direct key developmental transitions and germline specification likely through posttranscriptional regulation. These findings reveal a minimalist yet effective RNA silencing system and provide insights into the evolutionary versatility of AGO proteins in coordinating complex developmental programs across eukaryotes.
Abstract
ARGONAUTE (AGO) proteins are a highly conserved family of RNA-binding proteins that play central roles in gene regulation and developmental processes across eukaryotes. Although AGO family members have been extensively studied in animals and plants, where they are typically encoded by multiple genes, their function in brown algae, a diverse and complex group of multicellular algae, remains largely unknown. Here, we show that the genomes of several brown algae encode only a single AGO protein, containing the conserved functional domains characteristic of the family. Using the model brown alga Ectocarpus and a combination of cell biology, genetic, and transcriptomic approaches, we demonstrate that AGO is essential for the transition from vegetative growth to sexual reproductive development and for germline establishment. Our results further suggest that AGO functions in concert with microRNAs to regulate target genes primarily at the posttranscriptional level, likely through translational repression. Ectocarpus thus represents a rare example of a complex multicellular organism that relies on a single AGO protein to regulate key developmental processes, pointing to a minimalistic model of RNA-based regulation in brown algae.
