Abstract 2380: Separate but important roles of {alpha}SpII and FANCD2 in the FA pathway after DNA interstrand crosslink damage

Fanconi anemia (FA) is a genetic disorder characterized by bone marrow failure, an increased incidence of cancer, genomic instability, congenital abnormalities and a defect in ability to repair DNA interstrand crosslinks (ICLs). We have previously shown that FA cells have a deficiency in the structural protein, nonerythroid alpha spectrin (SpII), which is critical for repair of DNA ICLs and binds to crosslinked DNA. The FA protein, FANCD2, after monoubiquitination (FANCD2-Ub), has also been shown to be critical for ICL repair. However, the relationship between SpII and FANCD2 and whether they are involved in the same steps or events in this process is not known. The present study was undertaken to address these questions and to examine the role of SpII in the function of non-ubiquitinated FANCD2 (non-Ub FANCD2) and FANCD2-Ub in the FA pathway after ICL damage. Immunofluorescence microscopy was used to determine whether these proteins co-localize in nuclear foci after cells are damaged with an ICL agent, 8-methylpsoralen plus UVA light or mitomycin C. Time course measurements showed that formation of FANCD2 foci in normal human cells is different from those of SpII, FANCA and the ICL repair protein, XPF. FANCD2 foci were visible 2 hours after damage, plateaued at 16 hours and were still present at 72 hours. In contrast, SpII, FANCA and XPF foci were visible 10 hours after damage, peaked at 16 hours and by 24 hours were no longer observed. SpII foci, over this time course, did ...
Source: Cancer Research - Category: Cancer & Oncology Authors: Tags: Molecular and Cellular Biology Source Type: research