環境が駆動する原始細胞の「成長・選択・遺伝」の究明へ～凍結・融解が、さまざまな脂質組成の膜区画のふるまいに与える影響を探索～

2025-12-09 東京科学大学

図1. 本研究で実施した研究結果の模式図。
二種類のリン脂質で作製した区画に、それぞれ異なるDNA分子を内包成分として封入し、凍結・融解の操作を行った。その結果、膜区画のサイズの成長に伴って、成長に有利な性質を持つPLPCと、PLPCに封入していたDNA分子に組成が偏ることを検出した。すなわち、凍結・融解を繰り返す環境条件が原始細胞の「成長・選択・遺伝」を駆動しうることを示した。

<関連情報>

• https://www.isct.ac.jp/ja/news/n2ae9dvsu1xe
• https://pubs.rsc.org/en/content/articlelanding/2025/sc/d5sc04710b

氷環境におけるリン脂質区画の組成選択は、カプセル化された遺伝情報の濃縮を促進する Compositional selection of phospholipid compartments in icy environments drives the enrichment of encapsulated genetic information

Tatsuya Shinoda,Natsumi Noda,Takayoshi Watanabe,Kazumu Kaneko,Yasuhito Sekine and Tomoaki Matsuura
Chemical Science  Published:31 Oct 2025
DOI:https://doi.org/10.1039/D5SC04710B

Abstract

The lipid world hypothesis proposes that both intracellular components and the chemical composition of the membrane compartment can act as heritable information, contributing to protocellular fitness. However, there are few experimental demonstrations of membrane compositional selection, and none of them have expanded to the associated transfer of encapsulated contents, representing a possible early form of inheritance. Here, we quantitatively demonstrated that the growth of phospholipid vesicles depends on their lipid composition under freezing and thawing (F/T) cycling: vesicles with more unsaturated bonds in the acyl chain showed higher growth, membrane mixing, and content mixing efficiencies. When vesicles composed of phospholipids with either one or two unsaturated bonds were mixed and subjected to F/T cycles, a selective enrichment of the lipid with two unsaturated bonds was observed in the grown vesicles. Moreover, selection acting on lipid composition was propagated to the encapsulated genetic material, which was also enriched, while it did not play a particular role and thus was selectively neutral. We conclude that membrane lipid composition can be a direct target of selection for grown vesicles under an icy environment, leading to indirect but concurrent enrichment of compartmentalized genetic molecules—independent of their encoded information.