中国家蚕抗菌肽基因CBM1全长cDNA序列测定及其基因结构分析

Cloning and Sequencing of Antibacterial Peptide CBM1 in the Silkworm from China

用大肠杆菌感染中国家蚕(Bombyx mori)蛹,从中提取总RNA,用RT-PCR方法获得蚕抗菌肽基因CBM1 cDNA部分片段并克隆测序,以此蚕抗菌肽基因CBM1的部分片段,设计特异性引物,用3′、5′RACE的方法,获得蚕抗菌肽基因CBM1 cDNA的全长序列;用PCR的方法,从中国家蚕蛹基因组DNA获得抗菌肽CBM1基因的700 bp、1 100 bp左右的2个片段,初步证实中国家蚕抗菌肽基因在单倍体染色体中至少存在2个拷贝。

Template mRNA was prepared from fat body of chrysalis of the silkworm, Bombyx mori, 9 hours after injection of E. coli, K12D31. Partial cDNA fragments of cecropin CBM1 and cecropin CBM2 were obtained by reverse transcription PCR （RT-PCR） respectively. Gene specific primers were designed based on sequences of partial cDNA fragments of cecropins CBM1 and CBM2. A full-length sequence of cecropin CBM1 cDNA was obtained by 3＇RACE and 5＇RACE PCR and sequenced. With gene specific primers, three fragments of CBM1 gene were amplified from genomic DNA of the silkworm, B. mori from China by nested-primer PCR. They are about 700 bp, 1 100 bp and 1 600 bp in size, respectively. At least two copies of cecropin CBM1 gene about 700 bp and 1 100 bp in size have been proved.