Fig. 5

(A) Diagram of blind assay to assess CPT sensitivity showing embryos with severe body curvature or brain necrosis or lacking swim bladders. (B) Tdp1^−/+ fish were incrossed, and at 4 dpf, sibling embryos were treated with CPT (350, 500, and 750 nM) overnight. At 5 dpf, the most strongly affected embryos were blindly selected and genotyped. χ² = 4.902 with two degrees of freedom. The two-tailed P value is equal to 0.0862. (C) A female tdp1^−/− fish was crossed with a male tdp1^−/+ fish, and at 4 dpf, the embryos were treated with 500 and 1 μM CPT overnight. At 5 dpf, most strongly affected siblings were blindly selected at each concentration and genotyped. χ² = 0.391 with one degree of freedom. The two-tailed P value is equal to 0.5316. (D) Three-dpf embryos were treated with 14 μM CPT for 2 hours; then, TOP1-CC was examined using CsCl fractionation and immunoblotting, as described in Materials and Methods. (E) Quantification of (D); three biologically independent experiments, ±SEM. P values, two-tailed Student’s t test.