Whole Body Regeneration in a Colonial Ascidian, Botrylloides violaceus
Whole Body Regeneration in a Colonial Ascidian, Botrylloides violaceus
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DOI：
10.1002/jez.b.21303
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发表时间：
2009-12-15
影响因子：
2.2
通讯作者：
Swalla, Billie J.
中科院分区：
文献类型：
--
作者：
Brown, Federico D.;Keeling, Elena L.;Swalla, Billie J.
群体海鞘是唯一经历全身再生（WBR）的脊索动物，能够从外周血管形成一个全新的个体。在这里，我们描述了WBR在Botrylloides violaceus，一个殖民地海鞘，可靠地再生消融后的所有zooids和芽的年轻的殖民地。在早期再生过程中，几个芽在被膜脉管系统内发育，但只有一个芽继续发育成完整的子实体。我们描述了一些第一次事件的血管出芽导致的囊泡阶段与相差显微镜，延时录像和详细的组织学研究再生菌落。血管出芽的第一个明显阶段是单层细胞球被血管上皮包围。我们报告Piwi阳性细胞周围的再生血细胞的外观。我们观察到增殖细胞核抗原（PCNA）阳性细胞的循环血细胞在晚期再生的增加，并发现双标记的核表达与Piwi在一个子集的大循环细胞。我们很少发现Piwi或PCNA在血管出芽过程中分化组织，这表明在出芽和WBR过程中形成上皮组织的细胞主要来自循环血细胞前体。我们认为多种干细胞类型在B内循环。并且它们在WBR期间在分化成所有三个胚层的上皮组织之前在外周脉管系统中经历增殖。J. Exp. Zool.（Mol. Dev. Evol.）312 B：885-900，2009. (C)2009 Wiley-Liss，Inc.
Colonial ascidians are the only chordates to undergo whole body regeneration (WBR), the ability to form an entirely new individual from the peripheral vasculature. Here we describe WBR in Botrylloides violaceus, a colonial ascidian that reliably regenerates after ablation of all zooids and buds of young colonies. During early regeneration several buds develop within the tunic vasculature, but only one continues development into a complete zooid. We describe some of the first events of vascular budding leading to the vesicle stage with phase contrast microscopy, time-lapse video recording and detailed histological studies of regenerating colonies. The first conspicuous stage of vascular budding is when a single-layered sphere of cells becomes enclosed by vascular epithelium. We report the appearance of Piwi-positive cells in hemocytes surrounding the regenerates. We observed an increase of proliferating cell nuclear antigen (PCNA)-positive cells in circulatory hemocytes in late regenerates, and found double-labeled nuclear expression with Piwi in a subset of large circulatory cells. We rarely found Piwi or PCNA in differentiating tissues during vascular budding, suggesting that cells that form the epithelial tissues during budding and WBR originate mostly from circulatory hemocyte precursors. We propose that multiple stem cell types are circulating within B. violaceus and that they undergo proliferation in the peripheral vasculature before differentiating into epithelial tissues for all three germ layers during WBR. J. Exp. Zool. (Mol. Dev. Evol.) 312B:885-900, 2009. (C) 2009 Wiley-Liss, Inc.