Comparison of the effects of introducing the CRISPR/Cas9 system by microinjection and electroporation into porcine embryos at different stages

Table 1 Introduction of CRISPR/Cas9 system into embryos at different stages by cytoplasmic microinjection and electroporation

Embryonic stage	Gene editing method	Cas9/gRNAcomplex*	No. of embryos examined	No. (%) of embryos
Embryonic stage	Gene editing method	Cas9/gRNAcomplex*	No. of embryos examined	Cleavage**	Developed to blastocysts
1-cell	MI	−	201	138 (68.7 ± 2.6)^a	21 (10.5 ± 1.7)^a
	MI	+	248	155 (62.4 ± 2.9)^a	20 ( 8.1 ± 1.1)^a
	EP	−	210	192 (91.5 ± 1.7)^b	38 (18.1 ± 1.4)^ab
	EP	+	250	230 (92.0 ± 0.9)^b	40 (16.0 ± 3.1)^ab
2-cells	MI	−	105	78 (74.3 ± 1.7)^a	19 (18.2 ± 1.8)^ab
	MI	+	119	73 (61.5 ± 6.2)^a	15 (13.4 ± 6.4)^a
	EP	−	105	91 (86.9 ± 1.9)^b	34 (32.6 ± 1.9)^c
	EP	+	128	114 (89.7 ± 4.3)^b	33 (26.3 ± 7.7)^bc

MI microinjection, EP electroporation
All of the experiments were repeated four to five times. Data are expressed as the mean ± SEM
* The embryos at the 1-cell and 2-cell stages were microinjected and electroporated with (+) or without (−) gRNA and Cas9 complexes
** The embryos treated at 2-cell stage were defined as cleavage when they have more than 3 blastomeres on day 7
^a−cValues with different superscripts in the same column are significantly different (p < 0.05)

ISSN: 1756-0500