Kamimoto Mikiko, Suzuki Tohru, Ito Mutsumi, Miyake Akimitsu, Nakatsuji Norio, Nakatsuji Takako
Department of Marine Biology, Graduate School of Marine Science and Technology, Tokai University, Japan.
Int J Dev Biol. 2003 Feb;47(1):77-80.
The otx genes belong to the orthodenticle gene family and play important roles in anterior brain development in vertebrates. We isolated two cDNA sequences, one homologous to human and zebrafish otxl and another homologous to zebrafish otx3, from the teleost Leucopsarion petersii (shiro-uo), which belongs to the family of gobies in the Perciformes. During embryogenesis of shiro-uo, otx1 and otx3 were expressed in the fore- and mid-brain throughout development in a manner similar to that observed in other vertebrates so far studied. However, otx-1 mRNA was also present at earlier stages and we obtained unique results using in situ hybridization and RT-PCR analysis demonstrating that otx-1 signals showed a distinct increase in the upper blastomeres, but not in the lower blastomeres, at the 8-cell stage. These stronger signals were maintained in the animal pole blastomeres during the 16-cell to 64-cell stages, followed by a gradual decrease during blastula stages. Such unexpected unequal distribution of otx1 mRNA revealed that blastomeres at early cleavage stages already showed non-equivalence in the embryogenesis of shiro-uo.
otx基因属于正齿科基因家族，在脊椎动物前脑发育中发挥重要作用。我们从鲈形目虾虎鱼科的斑头舌鰕虎鱼（shiro-uo）中分离出两个cDNA序列，一个与人及斑马鱼的otx1同源，另一个与斑马鱼的otx3同源。在shiro-uo的胚胎发育过程中，otx1和otx3在整个发育过程中在前脑和中脑表达，其方式与迄今研究的其他脊椎动物中观察到的相似。然而，otx-1 mRNA在更早阶段也存在，并且我们通过原位杂交和逆转录聚合酶链反应（RT-PCR）分析获得了独特的结果，表明在8细胞期，otx-1信号在上层卵裂球中显著增加，而在下层卵裂球中没有增加。在16细胞至64细胞期，这些较强的信号在动物极卵裂球中得以维持，随后在囊胚期逐渐减弱。otx1 mRNA这种意外的不均等分布表明，在shiro-uo的胚胎发育中，早期卵裂阶段的卵裂球已经表现出不等同性。
