Cloning and expression patterns of two Smad genes during embryonic development and shell formation of the Pacific oyster Crassostrea gigas  

作　　者：刘刚 郇聘 刘保忠 

机构地区：[1]Institute of Oceanology,Chinese Academy of Sciences [2]University of Chinese Academy of Sciences

出　　处：《Chinese Journal of Oceanology and Limnology》2014年第6期1224-1231,共8页中国海洋湖沼学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(No.31001102);the National Basic Research Program of China(973 Program)(No.2010CB126403)

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.Increasing evidence indicates that transforming growth factor β(TGF-P) 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-P 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-P 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-P 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-P signaling pathways participate in the early development of bivalve mollusks,and suggest that further work is warranted to this end.

关 键 词：CALCIFICATION MOLLUSK shell field whole mount in situ hybridization SMAD transforming growthfactor β （TGF-β） 

分 类 号：S917.4[农业科学—水产科学]