Fig. 2: Cytoplasmic flows emerge during anaphase B and are independent of chromosome movement.
From: Cytoplasmic flow is a cell size sensor that scales anaphase
a, Time projection of mitochondria (Mito-GFP) and chromosomes (WGA). A flow pattern can be observed near the chromosomes. Scale bar, 50 µm. b,c, PIV analysis of the cell in a. The colour code represents flow velocity (b) and vorticity (c). The arrows represent the magnitude and orientation of the flow field. Grey mask, chromosomes. d, Flow velocity near the chromosomes for a compilation of 4-cell stage cells (n = 9 PIV measurements from 5 embryos) as a function of time. Three moments in anaphase are indicated: anaphase onset, anaphase A and anaphase B. Flows are stronger in anaphase B. The error bars represent s.e.m. e, Correlation between flow and chromosome velocity, for each timepoint 100–200 s after anaphase onset, for a compilation of 4-cell stage cells (n = 15 PIV measurements from 9 embryos, with 10 timepoints for each measurement). Fit, linear regression. f, Time lapse of two neighbour cells undergoing mitosis. The cell highlighted in orange lacks DNA (inset, no H1-488 labelling) and forms two asters, but not a mitotic spindle. The cell in grey is an internal control with DNA (inset, H1-488 labelling) that forms a normal mitotic spindle. DNA was false coloured in blue to facilitate visualization. Scale bars, 10 µm. g, Time lapse of a cell without DNA (no mitotic spindle formed). Mitotic stages are approximated due to the lack of chromosomes. Scale bars, 20 µm. h,i, PIV analysis of the cell in g. The colour code represents flow velocity and vorticity, respectively. The arrows represent the magnitude and orientation of the flow field. The inset in h shows the velocity profile along the axis of chromosome separation (grey line) in the cell in h and a control cell with DNA. The profiles are similar. AO, anaphase onset.
