Characterizing the interaction between FANCD2 and PCNA
Fanconi anemia (FA) is a rare recessive disorder characterized by hematological abnormalities, developmental defects, and pronounced cancer susceptibility. The disease is manifested by a mutation in any one of thirteen genes (FANCA, B, C, D1/BRCA2, D2, E, F, G, I, J/BRIP1, L, M, N/PALB2 ). FA genes encode the proteins that comprise the FA-BRCA pathway. The FA-BRCA pathway is activated following exposure to DNA damaging agents and during S-phase of the cell cycle. Eight of the FA proteins (FANCA, -B, -C, -E, -F, -G, -L and -M) form a multi-subunit ubiquitin ligase complex which facilitates the monoubiquitination of FANCD2 and FANCI. Although it is generally accepted that monoubiquitination targets these proteins to chromatin, the mechanism underlying the localization of FANCD2 and FANCI, as well as their specific role in DNA repair, are poorly understood. Proliferating Cell Nuclear Antigen (PCNA) is the major cellular DNA polymerase processivity factor and possible localizer of FANCD2. It has been previously demonstrated that PCNA and FANCD2 co-immunoprecipitate. Importantly, they also co-localize in discrete nuclear foci following exposure to DNA damaging agents. Furthermore, a highly conserved PCNA-interaction motif (PIP box) has been identified in FANCD2. Is there an additional protein facilitating co-immunoprecipitation and co-localization of PCNA and FANCD2 or is there a critical direct protein-protein interaction at the PIP box? Data collected using several established techniques (e.g. fluorescence polarization, in vitro pulldown, yeast two hybrid, and peptide competition) failed to support a direct protein-protein interaction.
"Characterizing the interaction between FANCD2 and PCNA"
Dissertations and Master's Theses (Campus Access).