Joint Study on Gene Expression in Early Einbryo

在本次与加州大学Fred Wilt博士合作的研究项目中，我们进行了一系列的研究，阐明了调控海胆胚胎形态发生的基因级联，得到了以下结果：1. 调控针状基质蛋白编码基因表达的HpEts基因在囊胚期被激活。HpEts在其5' UTR中包含T结构域。2. 克隆了海胆Tbr同源基因HpTbr的cDNA。HpTbr cDNA首先在胚前被检测到，在间质胚后消失。其表达位点仅限于特异性表达hpet的原代间质细胞，提示HpTbr与hpet基因的转录调控有关。3. HpLim是海胆XLim的同源基因，在植物性囊胚中短暂表达，通过向卵中引入大量HpLim mRNA而在全身表达HpLim的胚胎既不能形成内胚层和中胚层，也不能形成口轴和卵轴。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.