Tissue shape determines actin-dependent nuclear migration mechanisms in neuroepithelia

ABSTRACT Correct nuclear position is crucial for cellular function. Depending on cell context however, cytoskeletal elements and force generation mechanisms vary. While these mechanisms have been intensely studied in single cells, how nuclear positioning is linked to tissue morphology is less clear. Here, we compare apical nuclear positioning in developing straight and curved neuroepithelia of zebrafish. Interestingly, in differently shaped neuroepithelia the kinetics of nuclear positioning differ and we find that distinct actin-dependent mechanisms are employed. In straight neuroepithelia nuclear positioning is controlled by Rho-ROCK-dependent myosin contractility. Curved neuroepithelia use a formin-dependent pushing mechanism for which we propose a force generation theory. We suggest that cytoskeleton adaptability to tissue shape ensures correct nuclear positioning and robust epithelial maturation across different geometries. We further speculate that different mechanisms arise due to differences in actin arrangements during development, a theme highlighting the importance of developmental context for the execution of intracellular processes.