Delayed DNA replication, due to a transient inhibition of proteasome activity, is unlikely the cause of delayed transcriptional initiation. (A) EdU incorporation images stained with EdU (green, arrowheads) in
untreated (upper panel) and MG132-treated embryos (lower panel). (B) Immunofluorescence images of phosphorylation at serine residue 2 (Ser-2P) of Pol II (green) in untreated and aphidicolin-treated embryos.
Representative images of embryos stained with anti-H5 antibody (green, lower panel) for Ser-2P (arrowheads). Merge images show all images combined with. ♀, female pronucleus; ♂, male pronucleus; hpi, hours
post-insemination; scale bar = 50 µm.