RT Journal Article
SR Electronic
T1 Symmetry breaking and <em>de-novo</em> axis formation in <em>hydra</em> spheroids: the microtubule cytoskeleton as a pivotal element
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.01.14.906115
DO 10.1101/2020.01.14.906115
A1 Sander, Heike
A1 Pasula, Aravind
A1 Sander, Mathias
A1 Giri, Varun
A1 Terriac, Emmanuel
A1 Lautenschlaeger, Franziska
A1 Ott, Albrecht
YR 2020
UL http://biorxiv.org/content/early/2020/08/11/2020.01.14.906115.abstract
AB The establishment of polarity in cells and tissues is one of the first steps in multicellular development. The ‘eternal embryo’ hydra can completely regenerate from a disorganized cell cluster or a small fragment of tissue of about 10, 000 cells. During regeneration, the cells first form a hollow cell spheroid, which then undergoes de-novo symmetry breaking to irreversibly polarize. Here, we address the symmetry-related shape changes. Prior to axis establishment, the spheroid of regenerating cells presents inflation oscillations on several timescales that are isotropic in space. There are transient periods of fluctuations in defined arbitrary directions, until these undergo a clearly identified, irreversible transition to directed fluctuations along the future main axis of the regenerating hydra. Stabilized cytosolic actin structures disappear during the de-novo polarization, while polymerized microtubules remain. In our observations applied drugs that depolymerize actin filaments accelerate the symmetry breaking process, while drug-stabilized actin filaments prevent it. Nocodazole-depolymerized microtubules prevent symmetry breaking, but regeneration can be rescued by the microtubule-stabilizing drug paclitaxel at concentrations where microtubular structures start to reappear. We discuss the possibility that mechanical fluctuations induce the orientation and position of microtubules, which contribute to β-catenin nuclear translocation, to increase the organizer-forming-potential of the cells. Our data suggest that in regenerating hydra spheroids, microtubules play a pivotal role in the cooperative polarization process of the self-organizing hydra spheroid.Competing Interest StatementThe authors have declared no competing interest.