Skip to main content
. 2020 Aug 25;9:e54385. doi: 10.7554/eLife.54385

Figure 1. Polyploid cells accumulate in the adult Drosophila brain.

(A,B) Percentage of cells in individual brains exhibiting polyploidy in w1118 (A) and Canton-S (B) male and female whole brains. Age in days indicates days post-eclosion. Box plots showing range, dot indicates mean (n = 10). (Two-way ANOVA with greenhouse-geisser correction for unequal SDs followed by Holm-Sidak's multiple comparisons test. P values: ns > 0.1234;<0.0332 *;<0.0021 **;<0.0002 ***; ****<0.0001) (C) Accumulation of polyploidy is also observed in other Drosophila species. D.mauritiana and D.americana shown respectively in green and black compared to Oregon-R (D. melanogaster) shown in teal at different time points post-eclosion. Shapes indicate mean polyploidy observed, bars show range. three brains each per sample, n = 2 per time point. (D) Stacked bar plot showing proportion of polyploid cells with tetraploid or 4C DNA content (black) and greater than tetraploid or >4C DNA content (grey) in Canton-S males at different ages. (D) Percentage of polyploidy in Optic lobes (OL shown in purple), central brain (CB, shown in orange) and ventral nerve cord (VNC shown in blue) at different ages, w1118 (Error bars show mean ± SEM n = 3).

Figure 1—source data 1. Source Data for Figure 1A.
Figure 1—source data 2. Source Data for Figure 1B.

Figure 1.

Figure 1—figure supplement 1. Examples of flow cytometry and S-phase labeling.

Figure 1—figure supplement 1.

(A–C) Flow Cytometry gating strategy to ensure doublet discrimination. (D) The small population of mz19-GAL4, UAS nGFP labeled neurons are detectable by flow cytometry assay. (E) Dot plots showing DNA content during metamorphosis in Drosophila melanogaster w1118 brains. APF = after puparium formation. Cell cycle exit in most cells occurs by 24 hr APF. (F) Sparse EdU labeling observed in OL (outlined with yellow dotted line) before 10d but not after 2 weeks in the adult brain. (G) Increased DNA content observed in 60d old brains compared to 4d. Dot plots showing all cells in Elav-GAL4, UAS-nGFP brains at each time point Polyploid cells indicated as 4C and >4C. Elav-GAL4 driver shows weak expression in older brains.
Figure 1—figure supplement 2. Polyploidy in Optic lobes is not light or photoreceptor dependent.

Figure 1—figure supplement 2.

(A) 14d Canton-S (CS) males reared in 12 h L/D cycles do not show significantly different polyploidy compared to age-matched CS males reared in 24 hr darkness from eclosion. Error bars = mean ± SEM; unpaired t-test with welch’s correction. (B) Percentage of polyploidy observed in glass60j mutants lacking photoreceptors and age-matched w1118 controls at 1 and 14 days. Bars show mean % polyploidy in samples containing three pooled brains.