A hot spring Asgard archaeon sheds light on the origin of eukaryotic endosomal system.

Abstract Recent metagenomics studies have identified a novel archaeal superphylum namely Asgard, which are characterized by enriched eukaryotic-specific proteins. In this study, we screened unclassified archaeal genomes in public databases and obtained a high-qualified metagenome-assembled genome that can be assigned as a novel family-level Asgard member namely Odinarchaeceae Tengchong. Metabolic analysis indicates an autotrophic lifestyle of this hot spring archaeon with a complete tetrahydromethanopterin Wood-Ljungdahl pathway for carbon dioxide reduction and an arsenic efflux detoxification. Examination of public databases found that thus far Odinarchaeceae Tengchong may be the only prokaryote that encodes a C-terminal domain of Vps28 in the endosomal sorting complex required for transport (ESCRT), a critical connector of multiple ESCRT components. Therefore, the identification of this archaeon provides valuable evidence of the archaeal origin of eukaryotic ESCRT. We posit that all the key components of the eukaryotic endosomal system might have evolved from a common ancestor of Asgard archaea and eukaryotes.