Tarrason Risa, Gabriel;
(2021)
Archaeal roots of eukaryotic cell cycle control and ESCRT-III mediated cell division.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The life we see around us is predominantly eukaryotic, made of large multicellular organisms such as fungi, plants, and animals. However, all eukaryotes likely evolved more than a billion years ago from a gradual symbiotic merger of an archaeon and a bacterium. Since this time, eukaryotes have evolved and diversified, but certain fundamental features of their biology can be traced back to their archaeal-bacterial origins. In my PhD I have sought to apply this evolutionary perspective to shed light on universal principles of cellular growth and division by studying these processes in \textit{Sulfolobus acidocaldarius}, one of the closest relatives of eukaryotes that is also experimentally tractable. I focussed on the cell cycle, which in eukaryotes is marked by tightly controlled discrete cycles of DNA replication and cell division. These features are shared by \textit{S. acidocaldarius}. Progress through the eukaryotic cell cycle is controlled by cyclin-dependent kinases, whose activities oscillate due to coordinated waves of expression and proteasome-mediated degradation of cyclins. Contrastingly, neither \textit{S. acidocadarius} nor any other archaea known to date possess cyclins or cyclin-dependent kinases. In searching for other regulatory principles shared by the archaeal and eukaryotic cell cycle, we observed that \textit{S. acidocaldarius} cells use a pattern of oscillating gene expression and targeted proteasome-mediated degradation to complete their cell cycle – just as eukaryotes do. Specifically, we were able to show that cell constriction is triggered by targeted proteasome-mediated degradation of CdvB, an ESCRT-III homologue expressed in the run-up to cell division. These findings further support the idea that the eukaryotic cell cycle control has its origins in archaea and provide insight into how a minimal ESCRT-III system can cut the membrane.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Archaeal roots of eukaryotic cell cycle control and ESCRT-III mediated cell division |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2021. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Lab for Molecular Cell Bio MRC-UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10132115 |
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