Cloning and Prokaryotic Expression of Ubiquitin Gene of Spodoptera exigua multi-nucleocapsid nucleopolyhedrovirus

A ubiquitin gene of Spotoptera exigue multi-nucleopolyhedrovirus (SeMNPV) was cloned and sequenced．The result showed that the gene size was 243 bp，encoded 80 amino acids with apredicted size of 9．4kDa．To construct expressive vector for the udiquitin gene of SeMNPV．the frag． ment containing ubiquitin gene was inserted into pET-28a expressive vector．Expression of the fusion protein was induced by IPTG in E．coli BL2 1 fDE3)．By changing the time induced and the content of IPTG．the fusion protein had an optional expression leve1．The fusion protein was identified by West． elXl blot with a mouse Ab anti Ubiquitin from bovine oringe．To do the further study ， the specific Ab anti viral Ubiquitin was produced．In addition． the sequence of amino acids was analyzed with the software of Gendoc．Th e result displayed that ubiquitin of baculoviruses had some different amino acid substitutes in some residues and the amino acid sizes varied a lot compared with eukaryotic udiquitin． From these，we reckon that ubiqtuitins of baculovirus may have a unique way in the gene evolution