Fig. 2

Cell death in wildtype doomed muscles observed by confocal microscopy. All images show dorsal views (anterior left) of prepupal (a, b) and pupal (c-h) abdominal regions. Muscles were labeled with Mhc-tau-GFP (green) and myonuclei with UAS-histone-mKO (red, except for a’, b’ in white and h, i, j in magenta) driven by Mef2-Gal4. (a-g) correspond to the same specimen. (a, b) Disintegration of DEOM1s is initiated prior to HE and accompanied by condensation of myonuclei (a’, b’). Muscles outlined in (a, b) were magnified two-fold in panels (A’/B’). (c-h) Doomed muscles break apart into sarcolytes (arrow heads) which contain tau-GFP and, occasionally, condensed nuclei. (c, d) More laterally positioned DEOM2s undergo histolysis after completion of HE. (h) High magnification image of a DIOM1 located in the left hemi-segment of A2 on the second day of pupation surrounded by fluorescently labeled sarcolytes that persist for up to 3 days. (i, j) UAS-histone-mKO labeled cells driven by 24B-Gal4. (i) PCD of mono-nucleated, non-muscle cells (see Additional file 2: Figure S1) is associated with nuclear fragmentation following nuclear condensation. (j) In contrast, muscle fibers like the DEOM2 show condensation but not fragmentation of nuclei