Fig. 4: Cytoplasm versus nuclear rheology.
a–c, Representative bright-field (i) and confocal (ii) images of a zebrafish progenitor cell stained with Hoechst (blue) to label the nucleus and expressing Lap2β-GFP (green) with a microsphere in its cytoplasm (cyto) (a), nuclear interface (i/f) (b) and inside the nucleus (nuc) (c). Frequency spectrum of the complex G modulus, indicating the storage (closed symbols) and loss (open symbols) moduli of the three corresponding compartments (iii). Scale bars, 10 µm. Supplementary Video 3 shows the complete routine. d, Stiffness (Cα) of the cytoplasm, nuclear interface and nucleoplasm for controlm F-actin depolymerization (LatA) and LMNA overexpression conditions as extracted from the fit of a fractional Kelvin–Voigt model to the rheological spectrum. The lines connect paired data points that were acquired in the same cell with the same microsphere. For control cells, the experiments were independently repeated n = 9, 9 and 3 times for cyto, i/f and nuc, respectively. For LatA, n = 7, 7 and 3 and for lamin A, n = 4, 4 and 1, respectively. P values above the brackets derived from a paired t-test. Extended Data Fig. 5 and Supplementary Table 1 show a comparison of all the other fit parameters and their P values. N is the number of cells used in the measurement. e, P values of the indicated pairwise comparison using a two-sided Mann–Whitney U-test for Cα of the cytoplasm, nuclear interface and nucleoplasm in control, LatA treatment and lamin A (LMNA) overexpression.
