Barr, Genevieve;
(2022)
Investigating the relationship between the murine leukaemia virus p12 and capsid proteins.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Retroviral capsid (CA) proteins assemble into a hexameric lattice which forms the outer surface of the mature viral core. The CA lattice is a meta-stable structure with various functions and must disassemble at the correct point in replication for infection to occur. How lattice stability and disassembly (uncoating) are regulated is unknown. In Gammaretroviruses such as murine leukemia virus (MLV), the additional Gag cleavage product, p12, binds to and stabilises the mature CA lattice by an unknown mechanism. Following breakdown of the nuclear envelope during mitosis, the C-terminus of p12 binds to histones and thus tethers the CA-containing pre-integration complex (PIC) to host chromatin ready for integration. This thesis investigates the molecular and mechanistic details of the p12-CA interaction to elucidate the role of p12 in modulating core stability and uncoating. The p12-CA interaction differs between two strains of MLV, Moloney (Mo)-MLV and N-tropic (N)-MLV. I undertook a genetic screen and identified that six of the 11 CA residues which differ between the strains may be important for p12-CA binding. The effect of changing these CA residues on p12-CA binding and stability of the CA core were validated in vitro using purified proteins and virus-like particles. These were mapped onto existing CA structures to identify putative binding regions. I also investigated the role of p12-chromatin binding, and the timing and chronology of p12-CA versus p12-chromatin interactions, to understand the order of events which lead to uncoating. I suggest that p12 binds to a hydrophobic pocket at the NTD-CTD interface at sites of 3-fold symmetry, in order to stabilise the CTD-trimeric interface and hence the MLV CA core. Moreover, the p12-chromatin binding was shown to be a critical precursor to uncoating. Possibly, this interaction induces p12-CA dissociation in order to trigger uncoating of the MLV PIC at sites of integration.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Investigating the relationship between the murine leukaemia virus p12 and capsid proteins |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2022. 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 > 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 > Div of Biosciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10153532 |
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