长牡蛎两种engrailed同源基因的鉴定及其与贝壳发育相关性的研究

engrailed基因属于同源异形基因家族成员,在许多动物的分节、附肢发育、神经系统发育和贝壳形成过程中发挥作用。本研究克隆了长牡蛎两个engrailed同源基因,命名为cgi-eng1和cgi-eng2。序列分析表明,两个基因均具备典型engrailed基因保守的5个EH结构域。利用整装原位杂交技术检测了cgi-eng1和cgi-eng2在贝壳形成的关键时期早期D形幼虫时期的表达情况。结果显示,cgi-eng1和cgi-eng2 m RNA高表达于贝壳外缘,可能与早期贝壳形成过程有关。此外,两个基因的在贝壳外缘的表达模式亦有区别,提示两个基因的功能可能存在一定程度的分化。本研究首次系统鉴定了长牡蛎engrailed基因的成员,并发现它们可能均参与幼虫贝壳形成,研究结果有助于加深对贝类早期发育及贝壳形成的理解。

Identification of two engrailed-homologs in Crassostrea gigas and their potential involvement in larval shell formation

engrailed, a homeodomain-containing gene, functions in segmentation, limb development, central nervous system development and larval shell formation in many species. In the present study, we cloned two engrailed-homologs in Crassostrea gigas and designated them as cgi-eng1 and cgi-eng2. The expression patterns of the two engrailed-homologs were investigated in early D-veligers, which represented one crucial stage of shell development, using whole mount in situ hybridization (WMISH). The results showed that the two genes were highly expressed in the edge of shell field, indicating that cgi-eng1 and cgi-eng2 might participate in larval shell formation. Moreover, different expression patterns of cgi-eng1 and cgi-eng2indicated potential function differentiations of the two genes. This study firstly identified two engrailed-homolgs in C. gigas and predicted their potential roles in larval shell formation, which might shed new light on studies of early development of mollusks and molecular mechanisms of larval shell formation.