Table 1.

Efficiency of site-specific integration

Row	DNA*	DNA type	DNA size, kb	Strain	Background	F0 (n)	SS F0 (n)	Significance¶	SS, % (of F0)	R F0 (n)	R, % (of F0)
1	attB-pCA-GFP	Minicircle	~3	H11P	Mix	21	1	NS vs. row 2	4.8	1	4.8
2	attB-pCA-GFP	Minicircle	~3	H11P3	Mix	39	4		10.3	1	2.6
3	attB-pCA-GFP	Minicircle	~3	H11P3	FVB N4	15	6	P < 0.05 vs. row 2	40.0	3	20.0
4	attB-pCA-GFP-attB	Plasmid	~6	H11P3	FVB N4	38‡	6‖	—	15.8	1	2.6
5	attB-pCA-GFP, no RNA	Plasmid	~6	H11P3NVϕ	Mix	32‡	0	—	0.0	5	15.6
6	attB-pCA-GFP	Plasmid	~6	H11P3NVϕ	Mix	64§	10	NS vs. row 7	15.6	4	6.3
7	attB-pCA-GFP	Plasmid	~6	H11PNVϕ	Mix	30‡	2		6.7	0	0.0
8	attB-pCA-GFP-FRT5	Plasmid	~6	H11P	Mix	51	5	NS vs. row 9	9.8	3	5.9
9	attB-pCA-GFP-(FRT5)†	Plasmid	~6	H11P3	Mix	61	4		6.6	9	14.8
10	attB-pCA-GFP-FRT5	Plasmid	~6	H11P3	FVB N4	8	3	P < 0.05 vs. row 9	37.5	1	10.3
11	attB-pHB9-GFP-FRT5	Plasmid	~14	H11P3	FVB N4	66	2	—	3.0	2	3.0
12	attB-pCA-GFP	Plasmid	~6	R26P3NVϕ	Mix	22‡	2	—	9.1	2	9.1

Abbreviations: F0, embryos or animals obtained from injections; SS, site-specific integration; R, random integration; mix, mixed background of 129, C57BL/6 and DBA2; FVB N4, mice of the mixed background were outcrossed for 4 generations to the FVB strain and then intercrossed.

*All DNA was coinjected with ϕC31o mRNA, except for row 5.

^†Both FRT and non-FRT versions of attB-pCA-GFP were used.

^‡F0s were analyzed only as E10 or E11 embryos.

^§F0s were analyzed either as E10 or E11 embryos or as live pups.

^‖The six founders listed contained pCA-GFP without the bacterial backbone; five more founders with cassette exchange contained only the bacterial backbone. Therefore, the total number of founders with cassette exchange is 11 (29%).

^¶Fisher's exact test. NS, not significant.