All articles tagged with #cytokinesis
Researchers studying zebrafish embryos found that very large embryonic cells can divide without a fully closed actin contractile ring. Instead, they use a 'mechanical ratchet' system where cytoskeletal fibers and cycles of cytoplasmic stiffness—stabilized by microtubules—drive the contractile band inward step by step across several cell cycles, reshaping textbook views of cytokinesis in large eggs.
Researchers from the Brugués group at TU Dresden report in Nature a new mechanism for early embryonic cell division in yolk-rich cells: a mechanical ratchet that drives division without a fully closed actin contractile ring. By showing microtubule asters stiffen the cytoplasm during interphase and the cytoplasm becomes more fluid in M-phase, they find the actin band can ingress across multiple cell cycles, anchored by microtubules and re-stabilized when the cytoplasm stiffens again. This challenges textbook models and may apply broadly to yolk-rich embryos across species.