Haekkinen, H.-M. | bioRxiv Science

bioRxiv2026

A dynein-driven nucleokinesis program enables neural crest migration through confined tissues in vivo

Cell migration through confined tissue environments requires precise coordination between the nucleus and the cytoskeleton. Translocation of the nucleus through small pores is a limiting step in confined cell migration. Work in immune and cancer cells has illuminated a key role for actin polymerization and Myosin-II contractility in facilitating nucleus translocation through confinement. However, the microtubule cytoskeleton can also adaptively stabilise under confinement. Microtubule-dependent nucleokinesis constitutes an evolutionarily conserved cellular program ensuring directional nucleus translocation by deployment of cytoplasmic dynein motors. However, whether microtubule-driven nucleokinesis can operate during cell migration through confinement remained so far unexplored. The zebrafish neural crest (NC) provides a unique in vivo system to address this question. NC cells are a highly migratory, multipotent precursors of the vertebrate peripheral nervous system, which traverse diverse environments along the anterior-posterior axis of the embryo. In the head, cranial neural crest (cNC) cells migrate through loosely organised tissues, whereas trunk neural crest (tNC) cells navigate narrowly confined tissue spaces. Here, we show that tNC cells engage a microtubule motor-driven program of nuclear deformation and translocation during confined migration in vivo. Under confinement, tNC cells reorganize their microtubules from a perinuclear meshwork into a polarized, centrosome-associated bundle positioned ahead of the nucleus. Laser ablation reveals that this microtubule array actively pulls and deforms the nucleus. Using pharmacological and genetic approaches, we discover that dynein-dependent pulling forces enable nucleus translocation through confinement. Strikingly, this process occurs independently of Rho/ROCK/myosin II-mediated contractility, revealing a novel neuronal-like mode of nucleokinesis operating in confined tissue environments. Together, our findings uncover a conserved nuclear translocation program deployed during neural crest migration and suggest that microtubule-based nucleokinesis represents a fundamental strategy for navigating tissue confinement in vivo during both central and peripheral nervous system development.

cell biology↗

bioRxiv2025

In vivo nuclear envelope adaptation during cell migration across confining embryonic tissue environments

In physiology and in disease, cells often migrate through narrow spaces, such as leukocytes undergoing diapedesis or cancer cells during dissemination. Cultured cells under physical confinement have been shown to experience mechanical stress due to deformation of the nucleus. Nuclear deformation can lead to loss of nuclear integrity and DNA damage, and it has been proposed to underlie cancer initiation and progression. In vivo, the consequences of physical confinement on physiological, developmental cell migration remain so far unexplored. Here, we use the zebrafish neural crest as an in vivo model to address how multipotent embryonic cells respond to physical confinement during developmental migration. By measuring the extracellular space from head to tail along the embryonic body axis, we found that the level of tissue scale confinement increases along the antero-posterior axis. We found that neural crest experience dramatic nuclear deformation during their migrating between adjacent tissues, which quantitatively scales with tissue confinement. By using complementary genetic and mechanical strategies to ablate the surrounding tissue, we observe a rescue of nuclear deformation in vivo. Surprisingly, we found that while deformation of the NC nucleus causes stretching of the nuclear envelope, it does not cause DNA damage even upon extreme deformations. Instead, cells adapt, by decreasing both their DNA damage and LaminB2 levels upon entering confined spaces. In summary, we establish the neural crest as a physiological framework uncovering a dynamic adaptation to tissue confinement in vivo.

developmental biology↗