PT - JOURNAL ARTICLE AU - Wu, Yan AU - Lan, Yiling AU - Ononiwu, Favour AU - Poole, Abigail AU - Rasmussen, Kirsten AU - Da Silva, Jonah AU - Shamil, Abdalla Wael AU - Jao, Li-En AU - Hehnly, Heidi TI - Specific Mitotic Events Drive Cytoskeletal Remodeling Required for Left-Right Organizer Development AID - 10.1101/2024.05.12.593765 DP - 2024 Jan 01 TA - bioRxiv PG - 2024.05.12.593765 4099 - http://biorxiv.org/content/early/2024/10/01/2024.05.12.593765.short 4100 - http://biorxiv.org/content/early/2024/10/01/2024.05.12.593765.full AB - Cellular proliferation is vital for tissue development, including the Left-Right Organizer (LRO), a transient organ critical for establishing the vertebrate LR body plan. This study investigates cell redistribution and the role of specific progenitor cells in LRO formation, focusing on cell lineage and behavior. Using zebrafish as a model, we mapped all mitotic events in Kupffer’s Vesicle (KV), revealing an FGF-dependent, anteriorly enriched mitotic pattern. With a KV-specific fluorescent microtubule (MT) line, we observed that mitotic spindles align along the KV’s longest axis until the rosette stage, spindles that form after spin, and are excluded from KV. Early aligned spindles assemble cytokinetic bridges that point MT bundles toward a tight junction where a rosette will initially form. Post-abscission, repurposed MT bundles remain targeted at the rosette center, facilitating actin recruitment. Additional cells, both cytokinetic and non-cytokinetic, are incorporated into the rosette, repurposing or assembling MT bundles before actin recruitment. These findings show that initial divisions are crucial for rosette assembly, MT patterning, and actin remodeling during KV development.Competing Interest StatementThe authors have declared no competing interest.