bioimagesUnknownhttps://www.ebi.ac.uk/biostudies/studies/S-BIAD1167bioimagesSpecimenImage analysisAnnotationsFundingStudy ComponentorganisationBiosampleImage correlationAssociationsImage acquisitiondumollardbekkouchefalseReduction of cortical pulling at mitotic entry facilitates aster centrationEqual cell division relies upon astral microtubule-based centering mechanisms, yet how the interplay between mitotic entry, cortical force generation and long astral microtubules leads to symmetric cell division is not resolved.We report that a cortically located sperm aster displaying long astral microtubules that penetrate the whole zygote does not undergo centration until mitotic entry. At mitotic entry, we find that microtubule-based cortical pulling is lost. Quantitative measurements of cortical pulling and cytoplasmic pulling together with physical simulations suggested that a wavelike loss of cortical pulling at mitotic entry leads to aster centration based on cytoplasmic pulling. Cortical actin is lost from the cortex at mitotic entry coincident with a fall in cortical tension from ∼300pN/μm to ∼100pN/μm. Following the loss of cortical force generators at mitotic entry, long microtubule-based cytoplasmic pulling is sufficient to displace the aster towards the cell center. These data reveal how mitotic aster centration is coordinated with mitotic entry in chordate zygotes.2024-05-18T00:00:00Z2024-05-14T12:48:34.124Z2024-05-14T12:48:34.124ZS-BIAD1167