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. Author manuscript; available in PMC: 2013 Jan 15.
Published in final edited form as: Dev Biol. 2011 Oct 26;361(2):232–244. doi: 10.1016/j.ydbio.2011.10.024

Fig. 3. AMG divisions and apoptosis.

Fig. 3

(A–A″) Sagittal view of a single segment from a stage 12/0 sim-Gal4 UAS-tau-GFP embryo containing 5 AMG (asterisk and arrowheads). Anterior is to the left. Four wrapper+ AMG show nuclear and cytoplasmic tau-GFP (arrowheads). Of these, 2 are PH3+ (white arrowheads) and 2 are PH3− (yellow arrowheads). The PH3− cells are likely just beginning division prior to large scale phosphorylation of Histone H3. (B–D) Individual frames taken from a time-lapse imaging experiment of a glec-O1.5-Gal4 UAS-mCD8-GFP embryo at stage 13 in sagittal view focused around the AC. PMG from this segment are not shown, but PMG from the next anterior segment are present (PMG). Yellow circles indicate the single commissure prior to separation, red and white circles indicate the AC and PC respectively after separation, and elapsed time is shown (hh:mm:ss). (B) Initially, there are 10 AMG in this segment (asterisks). The 4 AMG that are in contact with the AC (white asterisks) will survive. The remaining AMG (yellow asterisks) will migrate inward and undergo apoptosis leaving a space between AMG and PMG from the next anterior segment. (C) Over the course of 52 minutes, 6 AMG fragment, and the debris is rapidly cleared. The yellow and red arrows indicate the progression of 2 AMG undergoing apoptosis. (D) After the wave of cell death, only 4 AMG remain (white asterisks). (E–G) Single segments from (E,F) stage 13 and (G) stage 14 sim-Gal4 UAS-tau-GFP embryos in sagittal view stained with anti-active Caspase-3 and anti-GFP. Yellow circle in (E) marks the position of the single commissure prior to separation, and red and white circles in (F) and (G) indicate the AC and PC, respectively. (E,F) During stage 13, AMG located at the anterior of the segment, and not in contact with the commissures, are active Caspase-3+ (white arrowheads). The position along the dorsal-ventral axis of active Caspase-3+ AMG varies. (G) During the period of sporadic AMG apoptosis (stage 14–16), both AMG that are at a distance from the AC (white arrowhead) and AMG that appear to contact the commissure (yellow arrowhead) are active Caspase-3+.