Nucleotide Sequence Analysis and Prokaryotic Expression of S7 cDNA from Dendrolimus punctatus CPV Hunan Strain

Abstract：The nucleotide sequence of genome S7 cDNA (AY 1 80908) from Dendrolimus punctatus cypovirus l Hunan strain(DpCPV—HN )was determined．S7 cDNA consists of 1 501 nucleotides and encodes a protein of 448 amino acids with a molecular mass of 49．8 kDa．Th e 5 ．an d 3 ．terminus conserved sequences are 5 一AGTAA一3 and 5 一GTTAGCC一3 。respectively． en compared wim S7 an d its putative protein of Lyman tria dispar cypovirus l an d Bombyx moil cypovirus 1．97．2％ an d 87．0％ identities in the nucleotide leve1．and 98．7％ an d 92．8％ identities in the amino acid level were found。repectively．BLAST search program revealed some similarity between DpCPV·HN P50 an d DnaK·like protein of Mycoplasma hominis．The cDNA fragment encoding DpCPV—HN P50 C259 was also cloned an d inserted into pET．28a expressive vector after being digested with BamH I an d日 d m to construct pET一28a／$7(59 1．1 37 1)recombinant expression vector．Expression of the fusion protein was induced by IPTG in E.col BL21．Th e results indicated that the fusion protein with a molecular mass of 37．3 kDa containing P50C259 was expressed abundan tly，and the fusion protein had an optional level when induced by 1．0mmol／L IPTG over about 2 hours．