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  • BRCA1 haploinsufficiency for replication stress suppression in primary cells.

BRCA1 haploinsufficiency for replication stress suppression in primary cells.

Nature communications (2014-11-18)
Shailja Pathania, Sangeeta Bade, Morwenna Le Guillou, Karly Burke, Rachel Reed, Christian Bowman-Colin, Ying Su, David T Ting, Kornelia Polyak, Andrea L Richardson, Jean Feunteun, Judy E Garber, David M Livingston
ABSTRACT

BRCA1-a breast and ovarian cancer suppressor gene-promotes genome integrity. To study the functionality of BRCA1 in the heterozygous state, we established a collection of primary human BRCA1(+/+) and BRCA1(mut/+) mammary epithelial cells and fibroblasts. Here we report that all BRCA1(mut/+) cells exhibited multiple normal BRCA1 functions, including the support of homologous recombination- type double-strand break repair (HR-DSBR), checkpoint functions, centrosome number control, spindle pole formation, Slug expression and satellite RNA suppression. In contrast, the same cells were defective in stalled replication fork repair and/or suppression of fork collapse, that is, replication stress. These defects were rescued by reconstituting BRCA1(mut/+) cells with wt BRCA1. In addition, we observed 'conditional' haploinsufficiency for HR-DSBR in BRCA1(mut/+) cells in the face of replication stress. Given the importance of replication stress in epithelial cancer development and of an HR defect in breast cancer pathogenesis, both defects are candidate contributors to tumorigenesis in BRCA1-deficient mammary tissue.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Anti-phospho-Histone H2A.X (Ser139) Antibody, clone JBW301, clone JBW301, Upstate®, from mouse
Sigma-Aldrich
Anti-γ-Tubulin antibody, Mouse monoclonal, clone GTU-88, ascites fluid
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Anti-Replication Protein A (Ab-1) Mouse mAb (RPA70-9), liquid, clone RPA70-9, Calbiochem®