HearSNPV orf83 encodes a late, nonstructural protein with an active chitin-binding domain

The ORF83 (ha83) of Helicoverpa armigera nucleopolyhedrovirus (HearSNPV) was characterized during the present study. Sequence analysis and chitin-binding assay revealed that Ha83 contained an active chitin-binding domain. Northern blot and Western blot analyses demonstrated that ha83 was expressed as a late gene and encoded a nonstructural protein of HearSNPV. Ha83 gene was transcribed beginning at 12h post-infection in infected Helicoverpa zea cells (HzAM1). Western blot analysis using a rabbit derived polyclonal antibody showed the product of ha83 in infected cells was a 20 kDa protein, in tune with the theoretical size of 18.8 kDa. The protein was first detected in the cytoplasm of infected HzAM1 cells at 12h p.i., and was transported later into the nucleus during infection.