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利用空斑技术，从既能形成多角体又含ＴＫ酶基因的苜蓿丫纹夜蛾重组核型多角体病毒ＡｃＭＮＰＶ－ＴＫ中，纯化了一株形成大立方形多角体的病毒突变株ＡｃＭＮＰＶ－ＴＫｍｔ５１３。用ＥｃｏＲＩ、ＰｓｔⅠ、ＢｇｌⅡ及ＫｐｎⅠ等限制性内切酶对它做了酶切分析，并克隆了多角体蛋白全基因及其侧翼部分的片段。对所克隆的部分全序列测定结果，发现在多角体蛋白基因读码框内只出现了一个碱基的突变，导致了第２５位的氨基酸密码子由ＧＧＴ变为ＧＡＴ，该位氨基酸由甘氨酸（Ｇｌｙ）变为天冬氨酸（Ａｓｐｑ）还利用ＰＣＲ技术扩增出突变了的多角体蛋白基因部分片段，并将它克隆入转移载体质粒ｐＥＶ５５，与不形成多角体的重组病毒ＴｎＮＰＶ－ＨＢｓＤ４ＤＮＡ共转染Ｓｆ９细胞，结果产生同样的大立方形多角体病毒。
A plaque-forming virus mutant AcMNPV-TKmt513 was successfully constructed from AcMNPV-TK, a recombinant telotrophic nuclear polyhedrosis virus, that can form polyhedrosis and TK genes. . It was digested with restriction enzymes EcoRI, PstI, BglII and KpnI and cloned the polyhedrin gene and its flanking part. A partial nucleotide sequence was cloned and found to contain only one base mutation in the reading frame of the polyhedrin gene, resulting in the change of the 25th amino acid codon from GGT to GAT. This amino acid consists of glycine ( Gly) to aspartic acid (Aspq). A partial fragment of the mutated polyhedrin gene was also amplified by PCR and cloned into the transfer vector pEV55 and the polyhedron-free recombinant TnNPV-HBsD4 DNA Transfection of Sf9 cells resulted in the same large cuboid polyhedrosis virus.