Abe Masanori, Takahashi Hiromi, Kuroda Reiko
Research Institute for Science and Technology, Tokyo University of Science, Yamazaki, Noda-shi, Chiba, Japan.
Int J Dev Biol. 2014;58(6-8):513-20. doi: 10.1387/ijdb.140087rk.
The handedness of gastropods is genetically determined, but the molecular nature of the gene responsible and the associated mechanisms remain unknown. In order to characterize the chiromorphogenesis pathway starting from the gene to the left-right asymmetric body plan, we have closely analyzed the cytoskeletal dynamics of the Physa (P.) acuta embryo, a fresh water non-dimorphic sinistral snail, during the early developmental stage by mechanically altering the handedness of the embryos at the critical spiral third cleavage. A fertile situs inversus was created and the nodal-Pitx gene expression patterns were completely mirror imaged to the wild type at the trochophore stage. Together with our previous work on Lymnaea (L.) stagnalis, we could show that chirality is established at the third cleavage, as dictated by the single handedness-determining gene locus, and then chirality information is transferred via subsequent spiral fourth and fifth cleavages to the later developmental stage, dictating the nodal-Pitx expression pathway. The cytoskeletal dynamics of manipulated and non-manipulated embryos of sinistral P. acuta and dextral dominant L. stagnalis are compared.
腹足纲动物的旋向是由基因决定的，但负责的基因的分子性质及相关机制仍不清楚。为了描述从基因到左右不对称身体结构的手性形态发生途径，我们通过在关键的螺旋第三次卵裂时机械改变胚胎的旋向，仔细分析了急性膀胱螺（Physa acuta）胚胎（一种淡水非二态左旋蜗牛）在早期发育阶段的细胞骨架动力学。创造出了一个可育的内脏反位个体，并且在担轮幼虫阶段，节点- Pitx基因的表达模式与野生型完全镜像。结合我们之前对椎实螺（Lymnaea stagnalis）的研究工作，我们可以表明，手性在第三次卵裂时确立，由单一的手性决定基因座决定，然后手性信息通过随后的螺旋第四次和第五次卵裂传递到后期发育阶段，决定节点- Pitx表达途径。比较了左旋急性膀胱螺和右旋占主导的椎实螺的操作胚胎和未操作胚胎的细胞骨架动力学。
