Sasamura T, Kobayashi T, Kojima S, Qadota H, Ohya Y, Masai I, Hotta Y
Department of Physics, Graduate School of Science, University of Tokyo, Bunkyo-ku, Japan.
Mol Gen Genet. 1997 May 20;254(5):486-94. doi: 10.1007/s004380050443.
We have isolated eight genes from Drosophila, small GTPases. They can be classified into three rab family genes (Drab2, Drab5, Drab11) and five rho family genes (Drac1a, Drac1b, Drac3, Dcdc42, DrhoA). While Drac3 is a novel type of rac gene, others are homologues of known mammalian genes for small GTPases. Northern blot analyses showed that all the genes are expressed throughout all developmental stages from embryo to adult. In situ hybridization to embryos revealed that Drab2, Drac1b, and Drac3 are highly expressed in the nervous system, in the trunk mesoderm, and in the cephalic mesoderm, respectively. Since hemocytes are derived from the cephalic mesoderm, we carried out double stainings using a hemocyte marker anti-peroxidasin antibody and Drac3 in situ hybridization. We found that Drac3 is expressed in hemocyte precursor cells. In the Drac3 deficiency embryos, the hemocyte precursor cells start to differentiate normally, but never develop into mature hemocytes, indicating that Drac3 is essential for their maturation. The DrhoA and Dcdc42 genes complemented S. cerevisiae rho1 and cdc42 mutations in the same manner as human rhoA and CDC42, respectively. These results suggest functional similarity between Drosophila and mammalian small GTPase genes.
我们从果蝇中分离出了八个基因，即小GTP酶。它们可分为三个rab家族基因（Drab2、Drab5、Drab11）和五个rho家族基因（Drac1a、Drac1b、Drac3、Dcdc42、DrhoA）。虽然Drac3是一种新型的rac基因，但其他基因是已知哺乳动物小GTP酶基因的同源物。Northern印迹分析表明，所有这些基因在从胚胎到成虫的所有发育阶段均有表达。对胚胎进行原位杂交显示，Drab2、Drac1b和Drac3分别在神经系统、躯干中胚层和头部中胚层中高表达。由于血细胞起源于头部中胚层，我们使用血细胞标记抗过氧化物酶抗体和Drac3原位杂交进行了双重染色。我们发现Drac3在血细胞前体细胞中表达。在Drac3缺陷胚胎中，血细胞前体细胞开始正常分化，但从未发育成成熟血细胞，这表明Drac3对它们的成熟至关重要。DrhoA和Dcdc42基因分别以与人类rhoA和CDC42相同的方式互补酿酒酵母rho1和cdc42突变。这些结果表明果蝇和哺乳动物小GTP酶基因之间存在功能相似性。
