Sequence Analysis of Helicoverpa armigera Single—nucleocapsid Nucleopolyhedrovirus heficase Gene

In order to investigate the genomic organization of the single nucleocapid nucleopolyhedrovirus of Helicoverpa armigera ,the Eco R I N fragment located at 54.8～59.3 kbp of the viral genome was sequenced.The fragment contained 3 762 bp helicase gene potentially encoding a protein with a molecular mass of 146kDa.A late transcriptional motif,ATAAG,was found at 50nt upstream of the translational start codon ATG,while two TATA box was located at 112nt and 189nt upstream of ATG.A typical poly(A) signal was found at 12nt downstream of the translational stop codon.Compared HaSNPV helicase with the helicases of Autographa colifornica MNPV(AcMNPV),( Bombyx bori NPV (BmNPV), Lymantria dispar MNPV(LdMNPV) Spodoptera exigue MNPV (SeMNPV), Orgyia pseudotsugata MNPV (OpMNPV),and Xestia c nigrum granuloviurs(XcGV),only 5motifs(I,Ia,II,III,IV)were found conserved in baculovirus.The homology of the other two notifs (V and VI),which are also quite conserved in other helicases,were lowe