Figure 1.

Creation of a BRCA1KO^smi mouse. HSA-mER-Cre-mER mice (10) were crossed with BRCA1^fl/fl mice, which have flox sites flanking exon 11 within the BRCA1 gene (11). Exon 11 in the BRCA1 is the largest exon in the BRCA1 gene (∼3400 bp) accounting for 60% of coding sequence. Male mice positive for Cre and BRCA1^fl/fl were mated to female mice positive for BRCA1^fl/fl, but negative for Cre. Only offspring that were Cre⁺ were used in these studies. Ten-week-old HSA-Cre⁺ BRCA1 Flox^+/+ male and female mice were injected with 2 mg/d tamoxifen or vehicle solution for 5 consecutive days. In all figures, BRCA1KO^smi mice are referred to as KO and vehicle-injected mice as WT.