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Functional Characterization of a Novel Substitution in the Human DNA Repair Protein APLF

APLF (Aprataxin and Polynucleotide kinase/phosphatase-Like Factor) is an FHA (forkhead-associated)-domain-containing nuclear protein that facilitates the repair of single-strand and double-strand breaks (SSBs and DSBs). Specifically, the APLF-FHA domain mediates interactions with XRCC1 and XRCC4, factors involved in SSB and DSB repair, respectively. A novel substitution was identified in pancreatic cancer patients, where a conserved histidine was substituted to leucine (H42L) in the APLF-FHA domain. The functional and biological characterization of this “variant of unknown significance” was investigated. This thesis shows that the H42L substitution affects APLF phosphorylation, impairs APLF retention at laser-induced DNA breaks, disrupts protein-binding to XRCC1 but not to XRCC4, and reduces cell survival following irradiation and etoposide exposure. Collectively, these data suggest that the H42L substitution impacts APLF participation in global DNA damage repair. The findings from this work could provide insight into the role of APLF in genomic integrity and, moreover, in cancer predisposition.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OTU.1807/33567
Date27 November 2012
CreatorsTran, Diana
ContributorsKoch, Christine Anne
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
Languageen_ca
Detected LanguageEnglish
TypeThesis

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