Ordered progression of nematogenesis from stem cells through differentiation stages in the tentacle bulb of Clytia hemisphaerica (Hydrozoa, Cnidaria)
Ordered progression of nematogenesis from stem cells through differentiation stages in the tentacle bulb of Clytia hemisphaerica (Hydrozoa, Cnidaria)
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DOI：
10.1016/j.ydbio.2007.12.023
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发表时间：
2008-03-01
影响因子：
2.7
通讯作者：
Rabet, Nicolas
中科院分区：
文献类型：
--
作者：
Denker, Elsa;Manuel, Michael;Rabet, Nicolas
在刺胞细胞中产生的刺细胞（线虫细胞），可以被认为是一种典型的神经发生过程。大多数分子数据与淡水水螅有关，其中线母细胞的生产分散在整个体柱外胚层，然后成熟细胞迁移到触手。我们描述了半水螅水母（Clytia hemisphaerica hydromedusa）的触须线虫发生的特征，发现它局限于触须球茎的外胚层，这是触须基部的特殊肿胀。通过各种光学和电子显微镜技术的分析表明，虽然线虫发生的细胞方面与九头蛇相似，但时空特征明显更加有序。触须球茎生线状外胚层（TBE）被发现是极化的，从近端区（包括大多数未分化细胞）到触须起始的远端，连续的成线状细胞阶段有明显的进展。脉冲追踪标记实验表明，分化的成线虫细胞不断向触手尖端移动，并且在水螅虫中，成线虫的速度比在水螅虫中更快。已知线虫发生相关基因（Piwi、dickkopf-3、minicolens和NOWA）同源基因的紧凑表达域相应地沿着TBE交错排列。这些明显的特征使Clytia TBE成为理解调节线虫发生机制的一个有前途的实验系统。(C) 2007爱思唯尔公司版权所有。
Nematogenesis, the production of stinging cells (nematocytes) in Cnidaria, can be considered as a model neurogenic process. Most molecular data concern the freshwater polyp Hydra, in which nematocyte production is scattered throughout the body column ectoderm, the mature cells then migrating to the tentacles. We have characterized tentacular nematogenesis in the Clytia hemisphaerica hydromedusa, and found it to be confined to the ectoderm of the tentacle bulb, a specialized swelling at the tentacle base. Analysis by a variety of light and electron microscope techniques revealed that while cellular aspects of nematogenesis are similar to Hydra, the spatio-temporal characteristics are markedly more ordered. The tentacle bulb nematogenic ectoderm (TBE) was found to be polarized, with a clear progression of successive nematoblast stages from a proximal zone (comprising a majority of undifferentiated cells) to the distal end where the tentacle starts. Pulse-chase labelling experiments demonstrated a continuous displacement of differentiating nematoblasts towards the tentacle tip, and that nematogenesis proceeds more rapidly in Clytia than in Hydra. Compact expression domains of orthologues of known nematogenesis-associated genes (Piwi, dickkopf-3, minicollagens and NOWA) were correspondingly staggered along the TBE. These distinct characteristics make the Clytia TBE a promising experimental system for understanding the mechanisms regulating nematogenesis. (C) 2007 Elsevier Inc. All rights reserved.