Fig. 4: Sleep reduces DNA damage in neurons of cnidarians.
From: DNA damage modulates sleep drive in basal cnidarians with divergent chronotypes
a,b Average sleep time during 36 h under LD in C. andromeda (a) and N. vectensis (b). White, black, and red horizontal bars represent light, dark, and SD periods, respectively (C. andromeda: ZT17-23, N. vectensis: ZT20-ZT4). c, d Sleep time accumulation of the previous 12 h (sliding average) in C. andromeda (c) and N. vectensis (d) during 36 h under LD. Black arrowheads indicate sampling time for the DNA damage assay presented in (i–l). e Confocal z-projection of a C. andromeda rhopalium and adjacent peri-rhopalial tissue. White squares mark representative single nucleus in the mesoglea. Red asterisk indicates rhopalium. Scale bar 150 μm. f Confocal z-projection showing the mOrange-positive endodermal nervous system in tg(-2.4NvElav1b:mOrangeCAAX) N. vectensis. White squares mark representative single neurons. Scale bar 100 μm. g Representative images of cells in the peri-rhopalial tissue of C. andromeda sampled at ZT11, ZT23, and the following day (Day2 ZT11). Nucleus stained by DAPI (gray), and γH2AX foci (magenta) are stained using immunohistochemistry. Scale bar 4 μm. h Representative images of γH2AX staining (magenta) in mOrange-positive neurons (green) of tg(-2.4NvElav1b:mOrangeCAAX) N. vectensis sampled at ZT17, ZT8, and the following night (Night2 ZT17). Nucleus stained by DAPI (gray). Scale bar 2 μm. i, k Normalized number of γH2AX foci per nucleus of control and sleep-deprived C. andromeda under LD. i Control: Day1 (n = 24, 1.00 ± 0.64), Night (n = 22, 0.55 ± 0.55), Day2 (n = 26, 1.31 ± 0.63). k Sleep-deprived: Day1 (n = 27, 1.00 ± 1.09), Night (n = 31, 2.11 ± 1.13), Day2 (n = 28, 1.42 ± 1.12). Values are mean ± s.d. (n=rhopalia from 8-10 animals per time point). j, l Normalized number of γH2AX foci per nucleus of control and sleep-deprived N. vectensis under LD. j Control: Night1 (n = 19, 1.00 ± 0.52), Day (n = 19, 0.46 ± 0.30), Night2 (n = 15, 0.92 ± 0.64). l Sleep-deprived: Night1 (n = 24, 1.00 ± 0.75), Day (n = 26, 1.57 ± 1.02), Night2 (n = 25, 0.92 ± 0.80). Values are mean ± s.d. (n=animals). Data in (a–d) are presented as mean ± SEM. Boxplots show median (center line), interquartile range (box), minima/maxima (whiskers), and mean (black cross) in (i–l). Mann-Whitney Wilcoxon (two-tailed) for (i–l). Significance level in (i–l) represents *p < 0.05, **p < 0.01, ***p < 0.001.
