UV-induced DNA damage tolerance in TNP1. a) Evaluation of the UV-impaired reporter gene's template activity under various UV irradiation exposures. Prior to transfection into HEK293T cells, the pGL3/SV40/Luc plasmid was either undamaged (group 1) or exposed to UV irradiation at 960 J/m2 for 15, 20, 30, and 60 s (groups 2–5, respectively). Luciferase activity was quantified 48 h post-transfection. b) Comparative analysis of UV-induced DNA damage tolerance in TNP1 at 960 J/m2 for 60 s. The pGL3-Pro-UV-0s-pRL plasmid (described in the Materials and Methods) was used. Groups 1 and 2 indicate the pGL3-Pro-UV-0s-pRL plasmid's luciferase activity without TNP1 expression, without irradiation and with UV irradiation at 960 J/m2 for 60 s, respectively. Groups 3 and 4 show the luciferase activities of plasmids expressing mouse and dolphin TNP1, respectively, both under UV irradiation at 960 J/m2 for 60 s. Under the same UV irradiation level, groups 5–8 indicate the luciferase activities of dolphin TNP1 plasmids with four separate single-point mutations: K14R, Q34R, N45D, and S51Y, respectively. Group 9 shows the luciferase activity of dolphin TNP1 plasmids with all four-point mutations. Luciferase activity was measured 48 h post-transfection. Relative luciferase units (RLUs) were determined by normalizing the ratio of firefly luciferase to Renilla luciferase. Student's t-test (n = 3): *P < 0.05; **P < 0.01; ***P < 0.001; ns, not significant.
