The pentameric hydrocoel lobes organize adult pentameral structures in a sea cucumber, Apostichopus japonicus
The pentameric hydrocoel lobes organize adult pentameral structures in a sea cucumber, Apostichopus japonicus
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海参的五聚体水鞘叶组织成体五聚体结构
DOI：
10.1016/j.ydbio.2022.09.002
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发表时间：
2022
影响因子：
2.7
通讯作者：
Kondo Mariko
中科院分区：
文献类型：
--
作者：
Udagawa Sumio;Nagai Akiko;Kikuchi Mani;Omori Akihito;Tajika Atsushi;Saito Mieko;Miura Toru;Irie Naoki;Kamei Yasuhiro;Kondo Mariko
尽管棘皮动物是两侧对称动物之一，但在胚胎发育或变态过程中，棘皮动物的身体平面从两侧对称转变为五倍径向对称或五倍径向对称。虽然这种转变背后的发展机制的澄清将是理解他们独特的身体计划演变的基础，但它仍然知之甚少。在这方面，水腔，一个中胚层体腔形成于两侧幼虫的左侧，将是理解机制的线索，因为它是变态前出现的第一个五射线结构，并发育成成虫的水维管系统。通过对仿刺参（Apostichopus）发育过程的分析，我们发现其水腔表达肌球蛋白重链（myosin heavy chain）、原肌球蛋白（tropomyosin）、soxC和delav等与肌肉和神经形成相关的基因，提示水腔细胞对成体的肌肉和神经结构有重要作用。此外，其中一个水腔叶的消融导致了成年五分体结构的不完全发育。消融初级水腔叶导致触手减少，消融次级水腔叶导致水脉管和神经索减少。我们的研究结果表明，水腔叶可能作为一个潜在的组织中心，建立在棘皮动物的五射线体计划。
Despite being one of the bilaterians, the body plan of echinoderms shifts from bilateral symmetry to five-fold radial, or pentaradial symmetry during embryogenesis or their metamorphosis. While the clarification of the developmental mechanism behind this transition will be a basis for understanding their unique body plan evolution, it is still poorly understood. With this regard, the hydrocoel, a mesodermal coelom formed on the left side of bilateral larva, would be a clue for understanding the mechanism as it is the first pentaradial structure that appears before metamorphosis and develops into the water vascular system of adults. By analyzing the development of a sea cucumber,Apostichopus japonicus, we found that the hydrocoel expresses genes related in muscle and neural formation such asmyosin heavy chain,tropomyosin,soxC,andelav, implying that cells of the hydrocoel contributes to muscle and neural structures in the adult. Furthermore, ablation of one of the hydrocoel lobes led to incomplete development of adult pentameral structures. The ablation of primary hydrocoel lobes resulted in the reduction in tentacles and the ablation of secondary hydrocoel lobes resulted in the reduction in water vascular canals and nerve cords. Our findings suggest that the hydrocoel lobes may serve as a potential organizing center for establishing the pentaradial body plan in echinoderms.