We will perform insertional mutagenesis using murine stem cell virus (MSCV) to activate genes in ES cells using the viral LTR. The advantage of using retroviruses for insertional mutagenesis is that cloning of the insertion sites is relatively simple. ES cells with randomly inserted MSCV will be selected for viable clones after both copies of the functional Brca1 or Brca2 are disrupted. The advantage of using MSCV is that, unlike other retroviral vectors, its LTR can drive high levels of target gene expression in ES cells. In a complementary approach, we will also use an shRNA library-based screen to identify genes whose loss of function can rescue the BRCA1- or BRCA2-deficient ES cells. We will also use this genetic screen to rescue the lethality of ES cells expressing deleterious variants that disrupt a specific biological process, e.g. a variant known to be defective in the E3 ubiquitin ligase activity of BRCA1. It will be interesting to compare the suppressors identified in such cells with those identified in ES cells that completely lack BRCA1.We have identified a number of candidate genes that can rescue lethality of Brca2 null ES cells. Our current focus is on understaning the mechanism and the physiological relevance of these genetic interactors.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
Application #
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
National Cancer Institute Division of Basic Sciences
Zip Code
Dungrawala, Huzefa; Bhat, Kamakoti P; Le Meur, Rémy et al. (2017) RADX Promotes Genome Stability and Modulates Chemosensitivity by Regulating RAD51 at Replication Forks. Mol Cell 67:374-386.e5
Ding, Xia; Ray Chaudhuri, Arnab; Callen, Elsa et al. (2016) Synthetic viability by BRCA2 and PARP1/ARTD1 deficiencies. Nat Commun 7:12425
Ray Chaudhuri, Arnab; Callen, Elsa; Ding, Xia et al. (2016) Replication fork stability confers chemoresistance in BRCA-deficient cells. Nature 535:382-7