(
A) Changes in total animal cap volume, the fraction of the animal cap volume occupied by nuclei, and the size of individual nuclei for indicated stages. Volumes were measured by lightsheet microscopy of embryos injected with mRNA encoding H4-sfGFP and subsequent automated image analysis (error bars represent SEM, n = 3 embryos; offspring of transgenic PCNA-RFP was used to monitor integrity of imaged nuclei via a second color channel). (
B) Image sequences showing nuclear import of H4-sfGFP fusion protein at 32- to 64- and 128-cell stages. Color scaling was kept constant and linear within each stage. Images show a representative maximum z-projection of a subset of a 3D microscopy stack of one of the embryos used in A. (
C) The linear range of Western blots was determined using chromatin of sphere-stage embryos. Plotted are observed versus expected fold differences in H2B intensity using different numbers of embryos (n ≥ 3). Band intensities of test stages (
Figure 4F) were only used for the analysis when they fell within the linear range.