Wu Yan, Lan Yiling, Ononiwu Favour, Poole Abigail, Rasmussen Kirsten, Da Silva Jonah, Shamil Abdalla Wael, Jao Li-En, Hehnly Heidi
Department of Biology, Syracuse University, Syracuse, 13244 USA.
BioInspired Institute, Syracuse University, Syracuse, 13244 USA.
bioRxiv. 2024 Oct 1:2024.05.12.593765. doi: 10.1101/2024.05.12.593765.
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.
细胞增殖对于组织发育至关重要，包括左右组织者（LRO），这是一个对建立脊椎动物左右身体轴至关重要的临时器官。本研究调查了细胞重新分布以及特定祖细胞在LRO形成中的作用，重点关注细胞谱系和行为。以斑马鱼为模型，我们绘制了库普弗小泡（KV）中的所有有丝分裂事件，揭示了一种依赖成纤维细胞生长因子（FGF）、在前部富集的有丝分裂模式。利用KV特异性荧光微管（MT）系，我们观察到有丝分裂纺锤体沿KV最长轴排列，直到玫瑰花结阶段，旋转后形成的纺锤体，并被排除在KV之外。早期排列的纺锤体组装细胞分裂桥，将微管束指向一个紧密连接，玫瑰花结最初将在该紧密连接处形成。分裂后，重新利用的微管束仍然靶向玫瑰花结中心，促进肌动蛋白募集。更多细胞，包括进行细胞分裂的和不进行细胞分裂的，被纳入玫瑰花结，在肌动蛋白募集之前重新利用或组装微管束。这些发现表明，初始分裂对于KV发育过程中的玫瑰花结组装、微管模式形成和肌动蛋白重塑至关重要。
