中文摘要：

增加的证据显示表明小径玩的那个转变生长因素(TGF-) 在软体动物的早发展的许多重要角色。然而，有限信息有关他们的详细机制被知道。这里，我们描述鉴定，克隆并且二 Smad 基因的描述，表明小径的 TGF- 的关键部件，从和平的牡蛎 Crassostrea 十亿。二基因的顺序分析，指定了为 cgi-smad1/5/8 和 cgi-smad4，揭示保存功能的特征。二基因广泛地在胚胎和幼虫被表示，建议在 C 的早发展的多重角色。十亿。二基因的 mRNA 在 D 象限聚集了， cgi-smad4 高度在胚囊的背面的方面上被表示，显示 TGF- 发信号小径可以涉及在 C 的 dorsoventral patterning。十亿。而且，在不同阶段的胚胎的壳域里的二基因的高表达式层次建议了重要角色因为特别地表明小径的 TGF- 壳开发分阶段执行，包括起始的壳域的形成和幼虫的壳的 biomineralization。这研究的结果为阐明提供基本支持 TGF- 发信号小径怎么参予瓣鳃类软体动物的早发展，并且建议那个进一步的工作，被保证到这个目的。

英文摘要：

Increasing evidence indicates that transforming growth factor β （TGF-β） signaling pathways play many important roles in the early development of mollusks. However, limited information is known concerning their detailed mechanisms. Here, we describe the identification, cloning and characterization of two Smad genes, the key components of TGF-β signaling pathways, from the Pacific oyster Crassostrea gigas. Sequence analysis of the two genes, designated as cgi-smad1/5/8 and cgi-smad4, revealed conserved functional characteristics. The two genes were widely expressed in embryos and larvae, suggesting multiple roles in the early development of C. gigas. The mRNA of the two genes aggregated in the D quadrant and cgi-smad4 was highly expressed on the dorsal side of the gastrula, indicating that TGF-β signaling pathways may be involved in dorsoventral patterning in C. gigas. Furthermore, high expression levels of the two genes in the shell fields of embryos at different stages suggested important roles for TGF-β signaling pathways in particular phases of shell development, including the formation of the initial shell field and the biomineralization of larval shells. The results of this study provide fundamental support for elucidating how TGF-β signaling pathways participate in the early development of bivalve mollusks, and suggest that further work is warranted to this end.