Takatori Naohito, Satou Yutaka, Satoh Nori
Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Japan.
Mech Dev. 2002 Aug;116(1-2):235-8. doi: 10.1016/s0925-4773(02)00150-8.
The configuration of the ascidian tadpole larva represents the most simplified and primitive chordate body plan. The present study revealed that Ciona intestinalis contains two hedgehog genes (Ci-hh1 and Ci-hh2), which are likely to be independent duplicate genes in this animal and ancestral to the three types of hedgehog gene of vertebrates. Ci-hh1 was expressed maternally and its maternal transcript was distributed evenly in fertilized eggs and early embryos. Ci-hh2 was expressed zygotically in the tailbud embryo and its transcript was evident only in cells of the ventral nerve cord. The notochord cells did not express the hedgehog genes in Ciona embryos.
海鞘蝌蚪幼虫的形态代表了最简化和原始的脊索动物身体结构。本研究表明，玻璃海鞘含有两个刺猬基因（Ci-hh1和Ci-hh2），这两个基因在该动物中可能是独立的重复基因，并且是脊椎动物三种刺猬基因的祖先。Ci-hh1在母体中表达，其母体转录本在受精卵和早期胚胎中均匀分布。Ci-hh2在尾芽胚胎中合子表达，其转录本仅在腹侧神经索细胞中明显。在玻璃海鞘胚胎中，脊索细胞不表达刺猬基因。
