Marked decrease of ribosomal RNA in BmN cells infected with AcMNPV

The baculoviruses Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and Bombyx mori nucleopolyhedrovirus (BmNPV) have highly similar genome sequences but essentially nonoverlapping host ranges. Recent studies demonstrated the arrest of protein synthesis in BmN cells (BmNPV-permissive) infected with AcMNPV. We report here the arrest of cell proliferation in AcMNPV-infected BmN cells involving a marked decrease of ribosomal RNA (rRNA), which was not observed for BmNPV-infected BmN cells or for Sf-9 cells (AcMNPV-permissive) infected with AcMNPV or BmNPV. The arrest of protein synthesis in BmN cells using the de novo protein synthesis inhibitor, cycloheximide, didn't cause the decrease of rRNA, suggesting a unique function of AcMNPV in its ability to decrease rRNA in BmN cells.