Fig. 3. skpA mutants exhibit cell cycle defects. (A-E) Quantification of
cell cycle parameters. The CNSs from wildtype and
skpA– larvae of the indicated ages were assayed for
different cell cycle parameters. (A) Mitotic index is the number of
phosphorylated-histone H3 (P-histone H3)-positive cells per squashed field
observed with a 100x objective. (B) S phase index is the number of
BrdU-incorporating cells relative to the volume of DNA staining determined
from whole mount confocal analyses. (C) 2C:4C ratio is the ratio of cells with
a 2C versus a 4C DNA content, determined from CCD images of DAPI-stained
squashed CNSs. (D) Apoptosis index is the number of TUNEL-positive cells
relative to the volume of DNA staining. (E) S phase (%) is the percentage of
BrdU-incorporating salivary gland or fat body nuclei relative to the total
number of nuclei from larvae 3.5 days AED. Error bars in B, D and E represent
one standard deviation (n
4 CNSs). (F-H) Examples of BrdU
incorporation and TUNEL-labeling in wildtype and mutant tissues. Projections
of confocal sections through entire CNSs (F,G) or salivary glands and fat
bodies (H) are shown. Note the skpA– imaginal disc
(I.D.) with many TUNEL+ cells (G'). No BrdU-incorporating nuclei were
observed in skpA– fat bodies (F.B.), in contrast
with the neighboring salivary glands (S.G.) (H'). Bar, 30 µm.