Characterisation of a New p97 Adaptor in Genome Stability

Thesis

Cells are subjected to constant genotoxic stress arising from both endogenous and exogenous sources which can drive the development of a wide range of diseases, especially cancers. Therefore, repair of these lesions is essential to maintain genomic stability and health. The DNA damage response is a key aspect of this process and requires the temporal and spatial regulation of many different factors to orchestrate the repair process. This requires the action of the AAA ATPase p97 which acts as a molecular segregase in order to facilitate the turnover of proteins on chromatin. This is also a crucial process to prevent the collision of DNA replication and transcription machinery with DNA bound proteins and DNA structures. These processes require the action of p97 cofactors which direct p97 to specific substrates and biological functions. The role of p97 and its cofactors in the DNA damage response is beginning to emerge, however there is still much to be investigated. Therefore, this thesis focuses on the characterisation of a new p97 adaptor protein discovered during a Mass Spectrometry analysis of the p97 interactome in response to ionising radiation. This adaptor protein, which has been named Ionising Radiation Enhanced VCP Interacting Protein 1, or IREVIP1, is responsible for maintaining genome stability even in unchallenged conditions. IREVIP1 was found to interact directly with p97 via a SHP domain located in the C-terminus of IREVIP1, as well as with Topoisomerases, and is responsible for bridging their interaction. IREVIP1 was observed as being part of the replication fork, and was required to prevent the accumulation of Topoisomerase cleavage complexes. Thus, IREVIP1 could be required to prevent genomic instability arising from collisions with Topoisomerase cleavage complexes and DNA structures arising from excessive DNA torsion. Therefore, this thesis begins to characterise the novel adaptor IREVIP1 and its functions within the cell.

Authors: Wiseman, K

• DOI: 10.5287/ora-mjrgrbezk
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford