Table 1. Summary of gene targeting experiments in HT1080 and RAN10.

Exp.	Cells	DNA	Seln	N	C	T + R	T	R	RTF	RIF	ATF
1	HT1080	8, p	2.5			27	10	17	0.37
2.1	HT1080	6.5, i	2.5	13.5	25	15	4	11	0.27	1.36	0.49
2.2	HT1080	6.5, i	10	16.2	29	17	7	10	0.41	1.05	0.74
2.3	HT1080	4, i	10	16.2	39	23	9	14	0.39	1.47	0.94
3.1	HT1080	8, p	10	12.5	16	15	8	7	0.53	0.6	0.68
3.2	HT1080	8, p	10	12.5	20	18	9	9	0.50	0.8	0.8
3.3	HT1080	8, p	10, I	15	14	13	10	3	0.77	0.22	0.72
3.4	HT1080	8, p	10, I	12.5	23	20	15	5	0.75	0.46	1.38
4	RAN10	4, i	10	15	26	18	17	1	0.94	0.10	1.64
5.1	RAN10	4, i	10	10	28	26	18	8	0.69	0.86	1.94
5.2	RAN10	4, i	10	15	52	28	21	7	0.75	0.87	2.6
5.3	RAN10	4, i	10, I	7.5	33	30	28	2	0.93	0.29	4.11
5.4	RAN10	4, i	10, I	15	71	23	20	3	0.87	0.62	4.12
6.1	RAN10	4, i	10		3	3	3	0	1.0
6.2	RAN10	4, i	10, T		5	4	4	0	1.0

Exp., experiments with the same whole number (e.g. 2.1, 2.2) were done in parallel, on the same day. DNA, DNA electroporated; numbers indicate µg used; p, SalI-linearised p6gpt; i, purified SmaI–SalI insert from p6gpt. Seln, selection conditions; numbers indicate concentration (µg/ml) of MPA; I, IFN-pretreated; T, TSA-pretreated. N, number of cells electroporated (×10^–6). C, total number of colonies selected in MPA/X/IFN. T + R, number of colonies tested in PCR assay for gene targeting. T, number of targeted integrants as detected by PCR. R, number of random integrants as detected by PCR. RTF, relative targeting frequency = T/(T + R). RIF, random integration frequency (×10⁶) = RC/N(T + R). ATF, absolute targeting frequency (×10⁶) = TC/N(T + R).