马尾松毛虫质多角体病毒(湖南株)基因组s7节段(AYI80908)cDNA克隆及序列分析结果表明：S7由 1501个碱基组成，编码由448个氨基酸组成的分子量为49．8 kDa的多肽P50。5 末端和3 末端具有5 -AGTAA-3 和5 -GTrAGCC-3 末端保守序列。该基因组与舞毒蛾质多角体病毒l型和家蚕质多角体病毒1型s7节段有很高的 同源性，核苷酸序列同源性分别为97．2％和87．0％，氨基酸序列同源性分别为98．7％和92．8％。P50多肽与人型支 原体的DnaK样蛋白在C．末端有相似性。本文报道了编码P50 C259的cDNA序列的克隆并作了原核表达，当用 1．0 mmol／L皿P，I’G 诱导2h，分子量约为37_3 kDa的融合蛋白在大肠杆菌BL21中得到大量表达。

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．