Cloning and sequencing of the Helicoverpa armigera nuclear polyhedrosis virus DNA polymerase gene

A HBeAg gene fragment, which has some restriction endonucleased sites on both 5′ ends, including pre c signal peptide sequence and 5′ 447 bp of the HBcAg gene was amplified by PCR. The HBeAg gene fragment was cloned into the BmNPV transfer vector pBm030 and the chimeric vector pBmHBe was constructed. The BmN cells were co transfected with pBmHBe and Wt BmNPV DNA,therefore, the recombinant viruses were obtained by plaque purification. Analysis of the HBeAg antigenecity by ELISA showed that the highest titer in the cell cultural medium was up to a dilution of 1∶32000. Although HBeAg protein also presents in the BmN cells the titer was only 1:2000. The HBcAg protein was fewer than HBeAg (<1∶160) whatever in culture medium and in cells. the results showed that the BmN cells can recognize the HBeAg signal peptide sequence and cut it correctly for HBeAg. The BmN PV BmN cell system is considered to be much better than E.coli system for producing HBeAg protein.