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FANCD2: Fanconi Anemia and Cancer. Grete Dudek March 27, 2007. DNA Damage Types & Fixes. Interstrand Cross Links Double Strand Breaks Homologous recombination Non-homologous end joining Which way?. Proposed Repair of Cross-Link. Proposed Repair of Cross-Link.
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FANCD2: Fanconi Anemia and Cancer Grete Dudek March 27, 2007
DNA Damage Types & Fixes • Interstrand Cross Links • Double Strand Breaks • Homologous recombination • Non-homologous end joining • Which way?
Proposed Repair of Cross-Link • Problem 1: DNA lesion
Proposed Repair of Cross-Link • Problem 1: DNA lesion • Problem 2: Double stranded break intermediate
Proposed Repair of Cross-Link • Problem 1: DNA lesion • Problem 2: Double stranded break intermediate
Proposed FA Pathway BRCA1 start finish
Facts of Fanconi Anemia • 12 complimentation groups, 11 cloned • Radiation vs. Mitomycin-C • The intermediate of an ICL is a double strand break. FANCD2 mutants may have defect in sensing the inter-strand cross link or processing it. • Increased amount of non-homologous end joining in FANCD2 mutants
Knockout Mice • Null mutation • Smaller size • Micropthalmia (small eyes) • Germ cell problems- hypogonadism Day 1: normal in back
Knockout Mice • Abnormal tubules in testes • Increased apoptosis in the spermatocytes • Ovaries from adult females were also abnormal
Knockout Mice • Increased tumorigenesis in FancD2 -/- epithelial tissues • Slight increase in heterozygotes as well.
Autosomal Recessive Symptoms Predisposition for acute myelogenous leukemia and solid tumors. Median survival age is approx 12 years. Fanconi Anemia
Specific Mutations in Pathway • FA complex- needs all 8 functional proteins to monoubiquitinate FANCD2 • FANCD2- lysine to arginine mutation • BRCA2 (FANCD1) mutation
FANCD2 in Cancer • FANCD2 mutations lead to NHEJ • DNA damage leads to mutations in other important genes • Mouse model isn’t good enough, but FA is rare- one in 300,000 live births • Cisplatin • Pathway can be inhibited to serve as a chemosensitizer in cancer therapy.
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