The origin of eukaryotic cell organisation remains one of the great unknowns in the history of life on earth. However, there is growing consensus that eukaryotes likely arose from a merger between an Asgard archaeal cell and an alpha-proteobacterial cell over a billion years ago. The two partners made distinct genetic contributions to the consortium, since most genes regulating metabolism and lipid synthesis in modern eukaryotes appear to have an alpha-proteobacterial origin, while genes regulating eukaryotic information processing, cell shape, and cell division cycle control appear to be mostly of archaeal origin. Thus, if we wish to better understand the origins of the eukaryotic cell division cycle it is important to better understand archaeal cell biology.
This is the focus of this PhD project. In the course of this project, the student will explore how cell organisation is modified as archaeal cells grow and divide. Sulfolobus will be used as a genetically-tractable archaeal model, while Asgard archaea - the closest known archaeal relatives of eukaryotes – will be used to shed light on aspects of archaeal cell biology that remained relatively unchanged during the emergence of the eukaryotic cell.
Given the challenges of working with extremophiles, much of the project will involve engineering new tools to aid the cell biological analysis. The project will therefore involve the development of fluorescent labels and microfabricated chambers to aid archaeal live cell imaging, and the development of tools that enable the identification of Asgard archaeal cells imaged in mixed cultures using cryo-electron microscopy.
Overall, it is hoped that this work will open up the field of archaeal cell biology, will reveal important new aspects of archaeal cell biology, and will shed light on the origins of the eukaryotic cell division cycle.
References
Rodrigues-Oliveira et al. (2023) Actin cytoskeleton and complex cell architecture in an Asgard archaeon. Nature 613.7943: 332-339.
Van Wolferen et al. (2022) The cell biology of archaea. Nature Microbiology 7 (11), 1744-1755.
Baum B & Baum DA. (2020) The merger that made us. BMC Biology, 18(1):72.
Imachi et al., (2020) Isolation of an archaeon at the prokaryote- eukaryote interface. Nature, 577, 519–525
Tarrason Risa et al. The proteasome controls ESCRT-III-mediated cell division in an archaeon. (2020) Science 369(6504):eaaz2532.
Spang et al., (2015) Complex archaea that bridge the gap between prokaryotes and eukaryotes. Nature, 521, 173–179.
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López-Avilés S et al.(2009) Irreversibility of mitotic exit is the consequence of systems-level feedback. Nature, 459(7246):592-5.