Limited functions of Hox genes in the larval development of the ascidian Ciona intestinalis
Limited functions of Hox genes in the larval development of the ascidian Ciona intestinalis
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DOI：
10.1242/dev.046938
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发表时间：
2010-05-01
期刊：
影响因子：
4.6
通讯作者：
Saiga, Hidetoshi
中科院分区：
文献类型：
--
作者：
Ikuta, Tetsuro;Satoh, Nori;Saiga, Hidetoshi
在动物中，沿前后轴的区域特异性形态特征由许多发育基因控制，包括编码同源结构域转录因子的Hox基因。尽管Hox基因被认为在形态多样性的进化以及身体计划的建立中起着关键作用，但除了昆虫和线虫外，人们对Hox基因在无脊椎动物中的功能知之甚少。本研究通过对胚胎发育过程中表达的7个Hox基因的敲低实验，探讨了Hox基因在海鞘（Ciona ninteinalis）幼体发育过程中的作用。实验结果表明，Ci-Hox12通过维持尾端表皮中Ci-Fgf8/17/18和Ci-Wnt5的表达，在尾部发育中发挥重要作用。此外，有研究表明Ci-Hox10参与背内脏神经节gaba能神经元的发育。令人惊讶的是，Ci-Hox1、Ci-Hox2、Ci-Hox3、Ci-Hox4和Ci-Hox5基因的敲除并未在幼虫中引起任何一致的形态缺陷。此外，注射了抗Ci-Hox1、Ci-Hox3和Ci-Hox5的MOs的幼虫，神经元标记基因的表达不受影响。综上所述，尽管Ci-Hox10和Ci-Hox12在海鞘神经元和尾部发育中起重要作用，但Hox基因对海鞘幼虫发育的贡献可能有限。
In animals, region specific morphological characters along the anteroposterior axis are controlled by a number of developmental genes, including Hox genes encoding homeodomain transcription factors. Although Hox genes have been regarded to play a key role in the evolution of morphological diversity, as well as in the establishment of the body plan, little is known about the function of Hox genes in invertebrates, except for in insects and nematodes. The present study addresses the role of Hox genes in body patterning during the larval development of the ascidian Ciona intestinalis conducting knockdown experiments of the seven Hox genes expressed during embryogenesis. Experimental results have demonstrated that Ci-Hox12 plays an important role in tail development through the maintenance of expression of Ci-Fgf8/17/18 and Ci-Wnt5 in the tail tip epidermis. Additionally, it has been shown that Ci-Hox10 is involved in the development of GABAergic neurons in the dorsal visceral ganglion. Surprisingly, knockdown of Ci-Hox1, Ci-Hox2, Ci-Hox3, Ci-Hox4 and Ci-Hox5 did not give rise to any consistent morphological defects in the larvae. Furthermore, expression of neuronal marker genes was not affected in larvae injected with MOs against Ci-Hox1, Ci-Hox3 or Ci-Hox5. In conclusion, we suggest that the contribution of Hox genes to the larval development of the ascidian C. intestinalis might be limited, despite the fact that Ci-Hox10 and Ci-Hox12 play important roles in neuronal and tail development.