Analysis of large scale expression sequenced tags (ESTs) from the anural ascidian, Molgula tectiformis
Analysis of large scale expression sequenced tags (ESTs) from the anural ascidian, Molgula tectiformis
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DOI：
10.1016/j.ydbio.2007.03.035
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发表时间：
2007-07-15
影响因子：
2.7
通讯作者：
Satoh, Nori
中科院分区：
文献类型：
--
作者：
Gyoja, Fuki;Satou, Yutaka;Satoh, Nori
无尾海鞘的胚胎发生过程中没有尾巴的形成。这种发展模式是海鞘进化中多次独立获得的衍生特征。我们确定了大约20，000个EST（i. e.为了全面研究无尾海鞘Molgula tectiformis无尾进化的分子机制，对无尾海鞘Molgula tectiformis的成体性腺、卵裂胚、原肠胚/神经胚、孵化前胚胎和孵化幼虫的5'端和3'端各10，000个克隆进行了测序。对这些EST的分析表明，在该物种中，（1）在有尾目海鞘玻璃海鞘胚胎发育过程中大量表达的胚胎/幼虫肌肉结构基因的表达受到抑制，（2）编码与其他生物已知蛋白质不相似的蛋白质的基因大量表达，（3）编码与其他生物已知蛋白质不相似的蛋白质的基因大量表达。（3）与有尾海鞘变态时表达上调相似的基因在孵化后数小时内表达上调;（4）在35个推测的Brachyury下游组分的直向同源物中，有15个在ESTs中被发现，尽管该物种的脊索分化受到抑制。我们讨论了这些显着的结果，让洞察的分子机制（S）负责海鞘的无尾模式的发展。(c)2007年爱思唯尔公司All rights reserved.
Anural ascidians show embryogenesis during which tail formation does not take place. This mode of development is a derived character acquired several times independently in ascidian evolution. We identified approximately 20,000 each ESTs (i. e. 10,000 clones each were sequenced from both 5' and 3' ends) of adult gonads, cleaving-embryos, gastrulae/neurulae, embryos before hatching, and hatched larvae of the anural ascidian Molgula tectiformis, in order to comprehensively investigate the molecular mechanism of tailless evolution. Analyses of these ESTs showed that in this species, (1) the expression of embryonic/larval muscle structural genes which are expressed abundantly during embryogenesis of the urodele ascidian Ciona intestinalis, is suppressed; (2) genes that encode proteins with no similarity to known proteins of other organisms are abundantly expressed; (3) genes that show similarity with those up-regulated at metamorphosis in urodele ascidians are up-regulated within several hours after hatching; and (4) 15 of 35 putative orthologues of the downstream components of Brachyury, a key transcription factor for ascidian notochord formation, were found in the ESTs, even though differentiation of notochord is suppressed in this species. We discuss these remarkable results that allow insight into the molecular mechanism(s) responsible for the anural mode of ascidian development. (c) 2007 Elsevier Inc. All rights reserved.