Carbohydrate chains are the principal antigens by which Bacillus thuringiensis（Bt） identify receptor proteins. The interaction between the antigen and Bt causes a pore in the membrane of midgut epithelial cells of i...Carbohydrate chains are the principal antigens by which Bacillus thuringiensis（Bt） identify receptor proteins. The interaction between the antigen and Bt causes a pore in the membrane of midgut epithelial cells of insects. Receptor proteins, such as aminopeptidase N and alkaline phosphatase, are glycoproteins. Cadherin is another cell surface receptor protein which has potential glycosylation sites. Glycosyltransferase is very important for the synthesis and modification of receptor proteins. It can indirectly influence the function of Bt. The 1 950 bp full-length c DNA encoding β-1,3-galactosyltransferase was cloned from the the midgut of Helicoverpa armigera by degenerative PCR combined with RACE techniques（GAL-Harm, Gen Bank accession no.： GQ904195.1） with two potential N-glycosylation sites（^157NNTI^160 and ^272NKTL^275）. Protein sequence alignments revealed that H. armigera β-1,3-galactosyltransferase shared high identity with β-1,3-galactosyltransferase in other insect species. The expression level of the β-1,3-galactosyltransferase gene in Cry1Ac-resistant H. armigera larvae was 9.2-fold higher than that in susceptible strain. The function of β-1,3-galactosyltransferase was investigated using RNAi technique. The result showed Cry1 Ac enhanced the toxicity against the si RNA-treated larvae compared with non-si RNA-treated ones, which indicated β-1,3-galactosyltransferase played an important role for the insecticidal toxicity of Cry1 Ac in H. armigera.展开更多
唾液酸化路易斯-X(sialyl lewis x,Slex)是选择素家族的一个共同糖配体,通过与选择素竞争性地结合炎性细胞,可以抑制炎症反应。克隆表达Slex合成过程中的关键酶,就可以在体外进行Slex的生物合成,从而进行相关生物制剂的开发。α-1,3-岩...唾液酸化路易斯-X(sialyl lewis x,Slex)是选择素家族的一个共同糖配体,通过与选择素竞争性地结合炎性细胞,可以抑制炎症反应。克隆表达Slex合成过程中的关键酶,就可以在体外进行Slex的生物合成,从而进行相关生物制剂的开发。α-1,3-岩藻糖基转移酶(alpha-(1,3)-fucosyltransferase,FT)就是参与Slex生物合成过程的关键酶之一。利用相关软件对牛的FT基因进行了生物信息学的分析,了解了FT的相关理化性质。通过PCR的方法获得了FT基因,构建了重组质粒pMD19-FT,并亚克隆至表达载体pPIC9K。通过电转化将线性化的表达质粒pPIC9K-FT整合到宿主菌Pichia pastoris GS115基因组上,构建了重组酵母GS115-FT。经诱导表达后,SDS-PAGE检测到了目的蛋白质条带,证明了此基因在P.pastoris GS115中能够可溶性表达。展开更多
基金supported by the Key Technologies R&D Program of China during the 12th Five-Year Plan period (2012BAD19B05)the National Natural Science Foundation of China (30971921,31321004)
文摘Carbohydrate chains are the principal antigens by which Bacillus thuringiensis（Bt） identify receptor proteins. The interaction between the antigen and Bt causes a pore in the membrane of midgut epithelial cells of insects. Receptor proteins, such as aminopeptidase N and alkaline phosphatase, are glycoproteins. Cadherin is another cell surface receptor protein which has potential glycosylation sites. Glycosyltransferase is very important for the synthesis and modification of receptor proteins. It can indirectly influence the function of Bt. The 1 950 bp full-length c DNA encoding β-1,3-galactosyltransferase was cloned from the the midgut of Helicoverpa armigera by degenerative PCR combined with RACE techniques（GAL-Harm, Gen Bank accession no.： GQ904195.1） with two potential N-glycosylation sites（^157NNTI^160 and ^272NKTL^275）. Protein sequence alignments revealed that H. armigera β-1,3-galactosyltransferase shared high identity with β-1,3-galactosyltransferase in other insect species. The expression level of the β-1,3-galactosyltransferase gene in Cry1Ac-resistant H. armigera larvae was 9.2-fold higher than that in susceptible strain. The function of β-1,3-galactosyltransferase was investigated using RNAi technique. The result showed Cry1 Ac enhanced the toxicity against the si RNA-treated larvae compared with non-si RNA-treated ones, which indicated β-1,3-galactosyltransferase played an important role for the insecticidal toxicity of Cry1 Ac in H. armigera.
