Neurons derive from the more apical daughter in asymmetric divisions in the zebrafish neural tube

International audienceIn the developing CNS asymmetric cell division is critical to maintain the balanced production of differentiating neurons while also renewing the population of neural progenitors. In invertebrates this process depends on asymmetric inheritance of fate determinants during progenitor divisions. A similar mechanism is widely believed to underlie asymmetrically fated divisions in vertebrates but compelling evidence for this is missing. We use live imaging of individual progenitors in the intact zebrafish embryo CNS to test this hypothesis. We provide the first direct evidence that asymmetric inheritance of a subcellular domain is strongly correlated with asymmetric daughter fates and reveal an unexpected feature of this process. The daughter cell destined to become a neuron is derived from the more apical of the two daughters, while the more basal daughter inherits the basal process and replenishes the apical progenitor pool