家蚕体节极性基因(Bmdpp)的克隆与表达研究

Molecular Cloning and Expression Analysis of the Decapentaplegic Gene(Bmdpp) in the Silkworm,Bombyx mori

体节极性基因dpp是昆虫发育过程中的关键基因。采用生物信息学的方法,利用家蚕EST数据获得了家蚕dpp基因（Bmdpp）cDNA序列。该cDNA序列全长1 206 bp,ORF1 146 bp,编码381个氨基酸,预测蛋白分子质量38.6 kD,等电点9.18。将克隆的Bmdpp基因完整CDS序列亚克隆到pET-28a（＋）表达载体,转化、诱导后经SDS-PAGE电泳检测到约40 kD与预测分子质量相符的目的蛋白条带。对Bmdpp在家蚕胚胎不同发育时期的表达分析发现,该基因在受精614 h的表达量很低,甚至没有表达。这一表达模式和果蝇dpp基因在胚胎发育过程中的表达模式相似,推测Bmdpp在家蚕早期胚胎发育的背-腹轴分化中起作用。

Decapentaplegic gene dpp is essential in the embryonic development of insects.By means of bioinformatics,the silkworm（Bombyx mori） EST database was utilized to obtain cDNA sequence of the silkworm dpp gene designated as Bmdpp.The full-length cDNA sequence was 1 206 bp in size,which comprised an open reading frame of 1 146 bp and coded for a protein of 381 amino acid residues.The deduced molecular weight was 38.6 kD and pI 9.18.After the complete coding sequence of cloned Bmdpp gene was subcloned into expression vector pET-28a（＋） by transformation and was induced to express,a target protein band about 40 kD was detected in SDS-PAGE electrophoresis,which was consistent with the predicted molecular weight.Expression analyses of Bmdpp gene at different developmental stages indicated that there was very low level or even no expression during 6 to 14 hours after fertilization.This expression pattern was similar to that of Drosophila dpp gene during embryonic development.It was thus speculated that Bmdpp played a role in dorsal-ventral axis differentiation in early embryonic development of silkworm.