Figure 7.

Evaluation of genotoxicity and cytotoxicity of Vika. (A) Recombination specificity of Vika and Cre on the respective cryptic human and mouse chromosomal target sites. The − and + indicates absence or presence of L(+)-arabinose (100 μg/ml) in the growth medium. Non-recombined and recombined plasmids are denoted as two triangles and one triangle, respectively. M, marker; 2-log DNA ladder, NEB. (B) Evaluation of DNA damage induction by γ-H2AX assay 72 h after infection with indicated recombinase-expressing virus, n = 3. (C) Quantification of the γ-H2AX-positive cells either infected with virus for respective recombinase expression or treated with campthothecin for 2 h. Statistically significant increase of γ-H2AX signals is indicated by asterisks. Error bars indicate standard deviation of the mean value (** indicate P = 0.01). (D) Proliferation effects on expression of indicated recombinases in mouse NIH3T3 cells. Cells were infected with bicistronic retroviruses expressing respective recombinase linked to GFP. Every 72 h, cells were analyzed by flow cytometry. Error bars indicate standard deviation of the mean value, n = 2.