Comprehensive Mutational Analysis of the BRCA1-Associated DNA Helicase and Tumor-Suppressor FANCJ/BACH1/BRIP1

UMMS Affiliation

Department of Molecular, Cell and Cancer Biology; Department of Biochemistry and Molecular Pharmacology

Publication Date


Document Type



Cancer Biology | Enzymes and Coenzymes | Molecular Biology | Neoplasms


FANCJ (BRIP1/BACH1) is a hereditary breast and ovarian cancer (HBOC) gene encoding a DNA helicase. Similar to HBOC genes, BRCA1 and BRCA2, FANCJ is critical for processing DNA inter-strand crosslinks (ICL) induced by chemotherapeutics, such as cisplatin. Consequently, cells deficient in FANCJ or its catalytic activity are sensitive to ICL-inducing agents. Unfortunately, the majority of FANCJ clinical mutations remain uncharacterized, limiting therapeutic opportunities to effectively use cisplatin to treat tumors with mutated FANCJ. Here, we sought to perform a comprehensive screen to identify FANCJ loss-of-function (LOF) mutations. We developed a FANCJ lentivirus mutation library representing approximately 450 patient-derived FANCJ nonsense and missense mutations to introduce FANCJ mutants into FANCJ knockout (K/O) HeLa cells. We performed a high-throughput screen to identify FANCJ LOF mutants that, as compared with wild-type FANCJ, fail to robustly restore resistance to ICL-inducing agents, cisplatin or mitomycin C (MMC). On the basis of the failure to confer resistance to either cisplatin or MMC, we identified 26 missense and 25 nonsense LOF mutations. Nonsense mutations elucidated a relationship between location of truncation and ICL sensitivity, as the majority of nonsense mutations before amino acid 860 confer ICL sensitivity. Further validation of a subset of LOF mutations confirmed the ability of the screen to identify FANCJ mutations unable to confer ICL resistance. Finally, mapping the location of LOF mutations to a new homology model provides additional functional information.

IMPLICATIONS: We identify 51 FANCJ LOF mutations, providing important classification of FANCJ mutations that will afford additional therapeutic strategies for affected patients.


FANCJ, mutations, cancer

DOI of Published Version



Calvo JA, Fritchman B, Hernandez D, Persky NS, Johannessen CM, Piccioni F, Kelch BA, Cantor SB. Comprehensive Mutational Analysis of the BRCA1-Associated DNA Helicase and Tumor-Suppressor FANCJ/BACH1/BRIP1. Mol Cancer Res. 2021 Jun;19(6):1015-1025. doi: 10.1158/1541-7786.MCR-20-0828. Epub 2021 Feb 22. PMID: 33619228; PMCID: PMC8178215. Link to article on publisher's site

Journal/Book/Conference Title

Molecular cancer research : MCR

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Link to Article in PubMed

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