Dilution of stochastic forces in Drosophila embryos

The groups of Alim, Aspelmeier and Großhans (A10, A19) studied the spatial pattern formation of nuclei in syncytial Drosophila embryos, which is a crucial step for the subsequent cellularization and morphing of the embryo and a paradigm for collective processes in biology. Intuitively, doubling of nuclei in the Drosophila embryo would increase stochasticity in inter-nuclear-forces and thus counteract nuclear order. Contrary to this idea, the researchers found that collective nuclear order is established as cytoskeletal motors and thus the stochastic forces are diluted with subsequent nuclear divisions (Kaiser et al., Biophys. J. (2018) 114:1730-1740).



Nuclear dynamics in Drosophila embryos. Left: live image of a Drosophila embryo expressing Histone H2Av-GFP in interphase 13. Scale bar: 50 μm. Center: live image of Drosophila embryo expressing EB1-GFP to label the growing tips of microtubules. Nuclear positions are marked by orange dashed lines. Microtubules of neighbouring nuclei overlap (yellow arrows). Scale bar: 5 μm. Right: theoretical model to describe nuclear dynamics. Microtubules are shown in green, nuclei in orange, molecular motors in blue and centrosomes in black