“两广二号”家蚕抗病毒基因Bmlipase-1和BmSP-2克隆与原核表达

本研究以优良杂交品种"两广二号"家蚕为试材,克隆了该杂交品种家蚕两个抗家蚕核型多角体病毒(BmNPV)基因:脂肪酶基因Bmlipase-1和丝氨酸蛋白酶基因BmSP-2,测序并分别与不同品种蚕的同源基因序列进行比较。结果显示,"两广二号"家蚕Bmlipase-1基因ORF长度为885bp,编码294个氨基酸,BmSP-2扩增长度为855bp,编码284个氨基酸;它们的核苷酸和推导氨基酸序列同源性皆达92%以上,Bmlipase-1更保守,同源性大于99%";两广二号"家蚕的Bmlipase-1基因脂肪酶活化部位和BmSP-2基因酶催化三联体位点的氨基酸残基与不同品种蚕的完全相同。以上结果说明这两个抗病毒基因在蚕的遗传进化过程中高度保守,提示其可能在机体消化或者免疫防御方面起着重要生理作用。将这两个抗病毒基因在大肠杆菌BL21中进行融合表达,获得的融合Bmlipase-1和BmSP-2蛋白分子量分别为47kD和42kD左右。

The Cloning and Prokaryotic Expression of Antiviral Genes Bmlipase-1 and BmSP-2 from Silkworm "Liangguang No.2" (Bombyx mori)

The complete open reading frames(ORF) of two antiviral genes against Bombyx mori nucleopolyhedrovirus(BmNPV),lipase gene Bmlipase-1 and serine protease gene BmSP-2,were cloned from excellent hybrid silkworm"Liangguang No.2"(Bombyx mori).The cloned products were sequenced and analyzed with the homologs derived from other silkworm species.The results showed that Bmlipase-1 ORF was composed of 885 bp nucleotides encoding 294 amino acids and BmSP-2 ORF was composed of 855 bp nucleotides encoding 284 amino acids.They both reached more than 92% homologies in nucleotide and deduced amino acid sequences,especially for Bmlipase-1 which almost reached more than 99%.Amino acid residues for the lipase active site of Bmlipase-1 and serine protease catalytic triad of BmSP-2 from silkworm "Liangguang No.2"showed identical with those from other silkworm species.The data suggested that the two antiviral genes should be highly conserved during the evolution of silkworm species,and they maight play important roles in immune defence as well as food digestion.The two antiviral genes were expressed in E.coli BL21.The molecular weights of fused Bmlipase-1 and BmSP-2 were about 47 kD and 42 kD,respectively.