Fig. 3

Mitotic cells in hypopharyngeal gland primordia at stage P1. a-f Optical sections at various levels (indicated by the red line in the inset) through a hypopharyngeal gland at stage P1 labeled with DAPI and fluorophore-tagged phalloidin (F-actin). a and b Few nuclei are located in the apical region of the epithelium, but most of these are in mitotic stages (arrows). c and d Mid-epithelial sections are crowded with interphase nuclei. e and f The basal region of the epithelium contains nuclei with condensed chromatin (yellow arrowheads), some of them seem fragmented (red arrowheads). g and h Hypopharyngeal gland of P1 pupa labeled with an antibody against phosphorylated histone 3 (H3-P), DAPI and, phalloidin (F-actin) and presented as maximum intensity projections. H3-P stained numerous nuclei close to the lumen (asterisks) and a few nuclei in the basal region of the epithelium (arrows). Bars, a-f 20 μm; g and h 100 μm