Light on our dark past: Elucidating the deep archaeal roots of eukaryotic cellular complexity

Introduction

The origin of the eukaryotic cell, with its complex and compartmentalized features, represents a prime hallmark in the evolution of life on Earth. Yet, important details underpinning the emergence of cellular complexity of eukaryotic cells remain thus far unresolved.

Current Understanding

Current views support evolutionary scenarios in which the first eukaryotic cell evolved via a merger between an archaeal host cell and one or more bacterial endosymbionts. Recent phylogenomic work from my lab has shown that the archaeal host cell evolved from within the Asgard archaea, an archaeal clade uniquely displaying several eukaryote-like features.

Research Gaps

However, key aspects regarding the nature and biology of the archaeal host cell remain elusive, limiting our current understanding of the early stages of eukaryogenesis.

Project Overview: DARK-ROOTS

In DARK-ROOTS, my team will capitalize upon our unique position and foundational results, and use complementary approaches to elucidate the emergence of complex cellular features during eukaryogenesis.

Methodology

1. Anaerobic Cultivation: Building on encouraging preliminary results, we will use an advanced anaerobic cultivation infrastructure to enrich diverse Asgard archaeal lineages.

2. Microscopy Studies: We will use high-resolution and live microscopy approaches to study their cellular ultrastructures and cell biological properties.

3. Structural Biology: Furthermore, we will capitalize on recent breakthroughs in structural biology and use AI-guided structural genomics to uncover new eukaryotic signature proteins in Asgard archaea.

4. Protein Evolution: Finally, we will trace the evolution of Asgard archaeal proteins, focusing on homologs of proteins that give stature to the complex and compartmentalized nature in eukaryotic cells.

Conclusion

Altogether, building on a rich foundation of preliminary results, my group will bring new pieces of the enigmatic eukaryogenesis puzzle to the table by elucidating how intracellular complexity arose during the prokaryote-to-eukaryote transition.