Isolated lymphocytes from the patient were hypersensitive to chromosomal breakage induced by the DNA cross-linking agent, mitomycin C. Our detailed phenotypic analysis of the RAD51-associated atypical FA revealed clinical manifestations from the diverse population and a consistent FA phenotype characterized by chromosome instability, intellectual disability, radial ray abnormality, and microcephaly, but not bone marrow failure.
Deficiency in several of the classical human RAD51 paralogs [RAD51B, RAD51C, RAD51D, XRCC2 and XRCC3] is associated with cancer predisposition and Fanconi anemia.
Further research on this zebrafish FA model will lead to a deeper understanding of the molecular basis of bone marrow failure in FA and the cellular role of RAD51.
We demonstrate that inactivation of HR factors BRCA1, BRCA2, or RAD51 hypersensitizes cells to acetaldehyde treatment, in spite of the FA pathway being functional.
Collectively, our data reveal a mechanism that facilitates timely removal of RPA and RAD51 from DNA damage sites, which is crucial for progression to the late-phase HR and suppression of the FA phenotype.
Our results further interconnect the FA pathway with DNA replication and provide mechanistic insight into the role of RAD51 in recombination-independent mechanisms of genome maintenance.
Mechanistic studies revealed that G2-phase FA-deficient iPSCs possess large γH2AX-RAD51 foci indicative of accrued DNA damage, which correlated with activated DNA-damage signaling through CHK1.
Here we report on a de novo g.41022153G>A; p.Ala293Thr (NM_002875) missense mutation in one allele of the homologous recombination DNA repair gene RAD51 in an FA-like patient.
Here we report on a de novo g.41022153G>A; p.Ala293Thr (NM_002875) missense mutation in one allele of the homologous recombination DNA repair gene RAD51 in an FA-like patient.
In support of this hypothesis, the set of identified genes included known determinants of olaparib sensitivity, such as BRCA1, RAD51, and Fanconi's anemia susceptibility genes.
Germ-line mutations in PALB2 lead to a familial predisposition to breast and pancreatic cancer or to Fanconi Anemia subtype N. PALB2 performs its tumor suppressor role, at least in part, by supporting homologous recombination-type double strand break repair (HR-DSBR) through physical interactions with BRCA1, BRCA2, and RAD51.
RAD51C, a RAD51 paralog, has been implicated in homologous recombination (HR), and germ line mutations in RAD51C are known to cause Fanconi anemia (FA)-like disorder and breast and ovarian cancers.
A panel of GI cancer cell lines was screened for FA pathway inactivation applying FANCD2 monoubiquitination and FANCD2/RAD51 nuclear focus formation and a newly identified FA pathway-deficient cell line was functionally characterized.
Since cells from the FA-D1 and FA-J patient groups are both able to monoubiquitinate FANCD2, the "Rad51 foci phenotype" provides a convenient assay to distinguish between these two groups.
Several components of the Fanconi anaemia (FA) family of proteins allow the formation of the DNA repair complex foci formed by proteins such as BRCA1/2 and RAD51.
Here we show that rereplication activates the FA pathway both for the activation of a G2/M checkpoint and for repair processes, like recruitment of RAD51.
The proteins involved in FA act coordinately in the cellular response to DNA cross-links in a pathway that has been shown to interact physically or functionally with a variety of other proteins involved in DNA repair or cell cycle control, notably BRCA1, Rad51,ATM,ATR, and Nbs1.
Western blot analysis of the DNA repair proteins (hMre11, Rad50, and Rad51) did not reveal any abnormalities in protein expression levels or their migration patterns in the fibroblasts derived from an FA patient either before or after irradiation.