Figure 3.

Comparative analysis of Cre activity in different Split-Cre reconstitution systems.A, comparison of Cre recombinase activity levels after the transient transfection of different pairs of complementary Cre fragments. ΔN17Cre and the components of Split-GCN4-Cre, Split-Co-InCre, and Split-GFP-Cre were each inserted into the pMSCV-Thy1.1 expression reporter vector and used to transfect HEK 293T cells with the CAG-loxp-STOP-loxp-TdTomato Cre activity detection vector. The cells were harvested 20 h after transfection, and TdTomato⁺ cells were detected. B, the average frequencies of TdTomato⁺ cells among cells with different Cre expression levels (Thy1.1 low, medium, and high) in panel A are shown. The data shown are typical results from three experiments. The small horizontal bars indicate the mean ± SEM. ∗p < 0.05, ∗∗p < 0.01, and ∗∗∗p < 0.001 (ANOVA with Bonferroni post hoc test). HEK 293T, human embryonic kidney cancer cells 293T; ns, not significant.