Cellular characterization of cells from the Fanconi anemia complementation group, FA-D1/BRCA2.
Fanconi anemia (FA) is an inherited cancer-susceptibility disorder, characterized by genomic instability and hypersensitivity to DNA cross-linking agents. The discovery of biallelic BRCA2 mutations in the FA-D1 complementation group allows for the first time to study the characteristics of primary BRCA2-deficient human cells. FANCD1/BRCA2-deficient fibroblasts appeared hypersensitive to mitomycin C (MMC), slightly sensitive to methyl methane sulfonate (MMS), and like cells derived from other FA complementation groups, not sensitive to X-ray irradiation. However, unlike other FA cells, FA-D1 cells were slightly sensitive to UV irradiation. Despite the observed lack of X-ray sensitivity in cell survival, significant radioresistant DNA synthesis (RDS) was observed in the BRCA2-deficient fibroblasts but also in the FANCA-deficient fibroblasts, suggesting an impaired S-phase checkpoint. FA-D1/BRCA2 cells displayed greatly enhanced levels of spontaneous as well as MMC-induced chromosomal aberrations (CA), similar to cells deficient in homologous recombination (HR) and non-D1 FA cells. In contrast to Brca2-deficient rodent cells, FA-D1/BRCA2 cells showed normal sister chromatid exchange (SCE) levels, both spontaneous as well as after MMC treatment. Hence, these data indicate that human cells with biallelic BRCA2 mutations display typical features of both FA- and HR-deficient cells, which suggests that FANCD1/BRCA2 is part of the integrated FA/BRCA DNA damage response pathway but also controls other functions outside the FA pathway.
Godthelp
Barbara C
BC
Department of Toxicogenetics, Leiden University Medical Center, Building 2, Postzone S-6-P, 2300 RC, Leiden, The Netherlands.
van Buul
Paul P W
PP
Jaspers
Nicolaas G J
NG
Elghalbzouri-Maghrani
Elhaam
E
van Duijn-Goedhart
Annemarie
A
Arwert
Fré
F
Joenje
Hans
H
Zdzienicka
Małgorzata Z
MZ
D024682:BRCA2 Protein / Q000235:genetics*; D001761:Bleomycin / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D002869:Chromosome Aberrations / Q000187:drug effects / Q000528:radiation effects; D004249:DNA Damage / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D005199:Fanconi Anemia / Q000235:genetics / Q000473:pathology; D051856:Fanconi Anemia Complementation Group Proteins / Q000235:genetics*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D006801:Humans; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D016685:Mitomycin / Q000494:pharmacology; D012854:Sister Chromatid Exchange / Q000187:drug effects / Q000528:radiation effects
D024682:BRCA2 Protein; D051856:Fanconi Anemia Complementation Group Proteins; D001761:Bleomycin; D016685:Mitomycin; D008741:Methyl Methanesulfonate