Cellular and biochemical characterisation of PrimPol, a novel eukaryotic primase-polymerase involved in DNA damage tolerance

Rudd, Sean G (2013) Cellular and biochemical characterisation of PrimPol, a novel eukaryotic primase-polymerase involved in DNA damage tolerance. Doctoral thesis (PhD), University of Sussex.

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Abstract

Genome stability is of upmost importance to life. DNA polymerases are essential for the
duplication and maintenance of the genome but they cannot themselves begin synthesis
of a DNA chain, and require the activity of specialised RNA polymerases called primases.
In eukaryotic cells distinct enzymes catalyse these two essential processes. This thesis
contains the characterisation of coiled-coil domain containing protein (CCDC)111, a
previously uncharacterised protein conserved in a broad range of unicellular and
multicellular eukaryotes including humans. CCDC111 is a member of the archaeaoeukaroytic
primase (AEP) superfamily and uniquely for a eukaryotic enzyme possesses
both primase and polymerase activities, and was thus renamed PrimPol. The work in this
thesis implicates PrimPol in the process of DNA damage tolerance, a universal
mechanism by which cells complete genome duplication in spite of potentially lethal DNA
damage. The first results chapters detail the essential role of a PrimPol homologue
(TbPrimPol2) in the important protozoan pathogen Trypanosoma brucei. A combination
of molecular, cell biology, and biochemical analyses indicate a role for TbPrimPol2 in the
post-replication tolerance of endogenously occurring DNA damage using its trans-lesion
DNA synthesis activity. The remaining results chapters characterise PrimPol in human
cultured cells, and demonstrate that this enzyme is present in both the nucleus and
mitochondria. In the nucleus PrimPol functions in the cellular tolerance of ultraviolet (UV)-
induced DNA damage, and is required to protect xeroderma pigmentosum variant (XP-V)
cells, deficient in the UV lesion bypass polymerase Pol !, from the cytotoxic affects of
UV radiation. Together, this thesis establishes the involvement of PrimPol in DNA
damage tolerance from one of the earliest diverging eukaryotic organisms to man.

Item Type: Thesis (Doctoral)
Schools and Departments: School of Life Sciences > Biochemistry
Subjects: Q Science > QD Chemistry > QD0241 Organic chemistry > QD0415 Biochemistry
Q Science > QH Natural history > QH0301 Biology > QH0426 Genetics
Depositing User: Library Cataloguing
Date Deposited: 22 Aug 2013 14:18
Last Modified: 04 Nov 2015 12:08
URI: http://sro.sussex.ac.uk/id/eprint/45543

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