中文摘要：

几转变生长因素贝它(TGF ) 总科成员从软体动物被识别了。在脊椎动物在骨头形成上表明小径的 TGF 的重要效果把线索给信号 transduction 机制并且牡蛎的壳怎么被形成。不管多么，什么样的调停人，并且怎么涉及表明小径的软体动物的 TGF 他们在软体动物玩功能很好没由于 genomic 信息和失败的缺乏被解释建立牡蛎房间线。如果我们知道了染色体顺序，也就是说，我们能用 BLAST 程序(http://www.ncbi.nlm.nih.gov/)寻找 TGF 总科成员，并且如果我们建立了软体动物的房间，排队我们能 transfect 房间感兴趣的基因并且在另外的基因的表达式层次上检测它的影响，例如矩阵蛋白质。因此，调查是否在软体动物有类似的 TGF 小径，许多重要调停人应该被识别。在这份报纸，我们报导编码从珍珠牡蛎被孤立的一个 Smad3 相当或相同的事物(指明的 Pf-Smad3 ) 的 cDNA， Pinctada fucata。顺序排列证明 Pf-Smad3 包含 aDNA-bindingMH1 领域和一个 Runx2/Cbfa1-bindingMH2 领域，并且在脊椎动物与 Smad3 蛋白质分享极其高的类似。然而，在果蝇和 Caenorhabditis elegans 的 Smad 蛋白质与另外的 Smad3 蛋白质很不同。反向的抄写聚合酶链反应结果显示 Pf-Smad3 mRNA 在成年大头针无所不在地被表示。fucata 并且在不同发展阶段在不同层次被表示。在 situ 杂交，结果证明 Pf-Smad3 mRNA 主要在中间的褶层的外部上皮的房间和外部褶层的内部上皮的房间被表示，特别在沟附近。这些结果建议 Pf-Smad3 可能参加许多生理的过程，包括 biomineralization，在牡蛎。

英文摘要：

Several transforming growth factor beta （TGFβ） superfamily members have been identified from mollusks. The significant effects of TGFβ signaling pathways on bone formation in vertebrates give clues to the signal transduction mechanism and how the shell of oysters is formed. However, what kinds of mediators are involved in the molluscan TGFβ signaling pathways, and how they play their functions in mollusks has not been well explained due to a lack of genomic information and the failure to establish oyster cell lines. That is, if we knew the genome sequence we could search the TGFβ superfamily members using the BLAST program （http：// www.ncbi.nlm.nih.gov/）, and if we established the molluscan cell line, we could transfect the gene of interest to the cell and detect its influence on expression levels of other genes, such as the matrix proteins. Therefore, to investigate whether there are similar TGFβ pathways in mollusks, many important mediators should be identified. In this paper, we report a cDNA encoding a Smad3 homolog （designated Pf- Smad3） that was isolated from the pearl oyster, Pinctada fucata. Sequence alignment showed that Pf-Smad3 contains aDNA-bindingMHl domain anda Runx2/Cbfal-binding H2 domain, and shares an extremely high similarity with Smad3 proteins in vertebrates. However, Smad proteins in Drosophila and Caenorhabditis elegans are very different from other Smad3 proteins. Reverse transcriptionpolymerase chain reaction results indicated that Pf-Smad3 mRNA was expressed ubiquitously in adult P/n. fucata and was expressed at different levels at different developmental stages. In situ hybridization results showed that Pf-Smad3 mRNA was expressed mainly at the outer epithelial cells of the middle fold and the inner epithelial cells of the outer fold, especially around the gutter. These results suggested that Pf-Smad3 might take part in many physiological processes, including biomineralization, in oysters.