Shrinking of X. tropicalis nuclei and somatic cell nuclei. (A) Nuclei assembled de novo in X. tropicalis egg extract were subjected to the nuclear shrinking assay as described in Fig. 1. Kinase inhibitors were added to the same concentrations as in Fig. 2 A. (B and C) Nuclei were isolated from adult X. laevis liver, subjected to the nuclear shrinking assay, visualized with mAb414, and imaged by wide-field microscopy. n = 4 different liver nuclei preparations and extracts. Bar, 10 µm. (D) X. laevis liver nuclei treated with HI control extract or LEE were visualized by immunofluorescence using an antibody against lamin B1. Confocal imaging and quantification were performed as in Fig. 3. n = 4 different liver nuclei preparations and 3 extracts. ***, P < 0.005; **, P < 0.01; *, P < 0.05. Error bars represent SD.