Department of Ecology and Evolutionary Biology and Molecular Biology Institute University of California Los Angeles, Los Angeles, USA.
Institute of Molecular Evolution Heinrich-Heine-Universitaet Duesseldorf, Dusseldorf, Germany.
Trends Microbiol. 2019 Aug;27(8):703-714. doi: 10.1016/j.tim.2019.04.002. Epub 2019 May 7.
The eukaryotic lineage arose from bacterial and archaeal cells that underwent a symbiotic merger. At the origin of the eukaryote lineage, the bacterial partner contributed genes, metabolic energy, and the building blocks of the endomembrane system. What did the archaeal partner donate that made the eukaryotic experiment a success? The archaeal partner provided the potential for complex information processing. Archaeal histones were crucial in that regard by providing the basic functional unit with which eukaryotes organize DNA into nucleosomes, exert epigenetic control of gene expression, transcribe genes with CCAAT-box promoters, and a manifest cell cycle with condensed chromosomes. While mitochondrial energy lifted energetic constraints on eukaryotic protein production, histone-based chromatin organization paved the path to eukaryotic genome complexity, a critical hurdle en route to the evolution of complex cells.
真核生物谱系起源于经历共生合并的细菌和古菌细胞。在真核生物谱系的起源处，细菌伙伴贡献了基因、代谢能量和内膜系统的构建块。那么古菌伙伴提供了什么，使得真核生物实验取得成功呢？古菌伙伴提供了复杂信息处理的潜力。古菌组蛋白在这方面至关重要，它提供了基本的功能单位，使真核生物将 DNA 组织成核小体，对基因表达进行表观遗传控制，转录具有 CCAAT 盒启动子的基因，并具有凝聚染色体的明显细胞周期。虽然线粒体能量减轻了真核生物蛋白质生产的能量限制，但基于组蛋白的染色质组织为真核生物基因组的复杂性铺平了道路，这是复杂细胞进化过程中的一个关键障碍。
