EXPRESSION OF LACZ REPORTER GENE UNDER THE CONTROL OF THE POLYHEDRIN PROMOTER OF SPODOPTERA-LITURA NUCLEAR POLYHEDROSIS-VIRUS

Promoter function of the putative polyhedrin-encoding gene (polh) of S podoptera litura nuclear polyhedrosis virus (S1MNPV) was determined by transferring it to the Autographa californica nuclear polyhedrosis vi rus (AcMNPV) through the AcNPV polh based vector, pVL1393. Three trans fer vectors pCBT2, pCBT3 and pCBT4 were constructed by substituting th e promoter and the neighbouring sequences of AcNPV in pVL1393 by that of S1NPV. The Escherichia coli lacZ gene was placed downstream from th e S1NPV polh promoter in the hybrid transfer vector (pCBT) constructs. Co-transfection of Spodoptera frugiperda cells (Sf9) with each of the pCBTlacZ vector and wild-type AcNPV DNAs led to synthesis of beta-gal actosidase (beta Gal). The plaque-purified recombinant viruses (S1AcNP V.lacZ) expressing lacZ under the polh promoter of S1NPV are stable. T he highest beta Gal activity was obtained with S1AcNPV4.lacZ. Producti on of beta Gal with recombinant virus, S1AcNPV3.lacZ in which S1NPV po lh promoter is in the reverse orientation in the AcNPV genome, is 83% of that produced by S1AcNPV4.lacZ. These results indicate that the S1N PV polh promoter is active in the genetic environment of AcNPV; the po lh of S1NPV is phylogenetically related to AcNPV like other baculoviru ses.