The BRCA1-interacting helicase BRIP1 is deficient in Fanconi anemia

Seven Fanconi anemia - associated proteins ( FANCA, FANCB, FANCC, FANCE, FANCF, FANCG and FANCL) form a nuclear Fanconi anemia core complex that activates the monoubiquitination of FANCD2, targeting FANCD2 to BRCA1-containing nuclear foci. Cells from individuals with Fanconi anemia of complementation groups D1 and J ( FA- D1 and FA- J) have normal FANCD2 ubiquitination. Using genetic mapping, mutation identification and western- blot data, we identify the defective protein in FA- J cells as BRIP1 ( also called BACH1), a DNA helicase that is a binding partner of the breast cancer tumor suppressor BRCA1.