Cytokinesis and postabscission midbody remnants are regulated during mammalian brain development

Significance During prenatal brain development, neural stem cells must divide to produce billions of daughter cells. At early stages, they produce more stem cells. Later, they produce neurons. Errors in their divisions can result in abnormal brains. We address whether cytokinesis—cleavage furrowing and intercellular bridge severing (abscission)—occurs differently at different ages and in a small-brained mouse mutant of a kinesin motor protein gene. We developed a method to image neural stem cells undergoing cytokinesis in brain explants. We found that remnants of severed intercellular bridges are more likely to remain on daughter cells at earlier ages. In the kinesin gene mutant, bridge severing occurs faster. These findings suggest that precise regulations of cytokinesis are important during early brain development.