Joint Study on Gene Expression in Early Einbryo

在这项研究项目中，我们与加州大学的弗雷德·威尔特博士合作，开展了一系列研究，以阐明调控海胆胚胎形态发生的基因级联，并获得了以下结果。1.调控毛刺基质蛋白基因表达的HpEts基因在囊胚期被激活。HpEts在其5‘非编码区中含有T结构域。2.克隆了海胆Tbr的同源基因HpTbr。HpTbr基因首先在孵化前的囊胚中被检测到，并在间充质囊胚之后消失。其表达部位仅限于表达HpEts的原代间充质细胞，提示HpTbr与HpEts基因的转录调控有关。3.HpLim是XLim的海胆同源物，在胚泡的植物半部分瞬时表达，通过将大量HpLim基因导入卵子而在全身表达HpLim的胚胎既不能形成内胚层和中胚层，也不能形成口轴和流产轴。这表明HpLim与背腹轴形成所需的植物信号系统有关。

In this research project in cooperation with Dr. Fred Wilt of the California University, we performed a series of study to elucidate a gene cascade regulating morphogenesis of sea urchin embryos, and obtained following results. 1. Expression of HpEts gene that regulated expression of genes encoding spicule matrix proteins is activated at the blastula stage. HpEts contains T domain in its 5' UTR. 2. cDNA of HpTbr, a sea urchin homolog of Tbr, was cloned. HpTbr cDNA becomes first detectable in pre-hatching blastulae and disappears after mesenchyme blastulae. Site of its expression is restricted to primary mesenchyme cells that specifically expresses HpEts, suggesting that HpTbr is related to regulation of transcription of HpEts gene. 3. HpLim, a sea urchin homolog of XLim, is transiently expressed in the vegetal half of the blastulae, and the embryos that express HpLim throughout the whole body by introduction of a large amount of HpLim mRNA in to eggs failed to form neither endoderm and mesoderm nor the oral and aboral axis. This suggests that HpLim is related to a vegetal signalling system needed for dorsoventral axis formation.