Research Paper Volume 12, Issue 11 pp 10415—10426

CHK2 is essential for spindle assembly and DNA repair during the first cleavage of mouse embryos

Figure 3. CHK2 inhibition affected spindle morphology and chromosome alignment at the first cleavage of early mouse embryos. (A) Embryos at metaphase were stained with anti-α-tubulin (green) and counterstained with Hoechst 33342 to visualize chromosomes (blue). Unlike those in the control group, embryos in the 25 μM treatment group showed a variety of defects, including multipolar and nonpolar spindles. The chromosomes in embryos in the 25 μM treatment group were severely misaligned. Bar = 20 μm. (B) A significantly higher proportion of embryos in the 25 μM treatment group exhibited spindle defects than those in the control group (35.5 ± 5.51%, n = 173 vs. 20.3 ± 3.55%, n = 165, p < 0.001). (C) The incidence of chromosome misalignment was also higher in embryos in the 25 μM treatment group than in those in the control group (35.8 ± 2.80%, n = 81 vs. 18.7 ± 1.82%, n = 55, p < 0.05). ***significant difference (p < 0.001). *significant difference (p < 0.05). (D) Chromosomal aberrations were observed in embryos in the CHK2 inhibition group. Blue, DNA. Bar = 5 μm.