931564.fig.004
Figure 4: Double immunolocalization of SC35 (column (a)) and hyperphosphorylated form of RNA polymerase II (column (a′)) in mouse embryos. The hyperphosphorylated form of RNA polymerase II is not revealed in the pronuclei of 1-cell embryos (lines (a), (b)). The appropriate labeling begins to be detected only at the early 2-cell stage (line (c)). However, association of RNA polymerase II with SC35 domains (speckles) is observed already at this stage and increased when ZGA finishes (line (d)). Bar is 10 μm.