gp37 3’ UTR reduces protein production at the polyhedrin locus of Autographa californica multicapsid nucleopolyhedrovirus

Baculovirus is a double-stranded DNA virus widely used in agriculture for the biological control of insect pests and in the pharmaceutical industry for vaccine production, due to its safety in humans. The type species, Autographa californica multiple nucleopolyhedrovirus (AcMNPV), has a broad insect host range and is the most genetically characterized baculovirus. During infection of insect cells, early genes are transcribed by the host RNA polymerase II, while late and very late genes are transcribed by a virus-encoded RNA polymerase. One such late gene, gp37 , is considered non-essential for viral replication, though its biological function remains unclear. In this study, we constructed three pairs of recombinant viruses, each containing complementary reporter genes, to investigate the regulatory role of the gp37 3' untranslated region (3' UTR). Our results show that the gp37 3' UTR modulates the expression of polyhedrin, green fluorescent protein and luciferase genes even when driven by the same promoter. This suggests a post-transcriptional regulatory role for the gp37 3' UTR in gene expression.