Table 1.

Gene targeting frequencies in R26^CreERT2;Brca1^SCo/Δ ES cells

			G418-resistant colonies
	4OHT*	shRNA	Total analyzed	Non-targeted (%)	Targeted (%)
	−	NT	78	70 (90)	8 (10)
Rb	+	NT	78	78 (100)	0 (0)
	+	53BP1	160	158 (99)	2 (1)
	+	p53	124	124 (100)	0 (0)
	−	NT	56	47 (84)	9 (16)
Pim1	+	NT	11	11 (100)	0 (0)
	+	53BP1	47	43 (91.5)	4 (8.5)

^*4-hydroxytamoxifen (4OHT) was added to induce CreERT2-mediated deletion of the Brca1^SCo allele