Plays a role in the production of infectious budded virion (BV) and occlusion-derived virion (ODV) formation. Associated with the envelopes of virions present in the nucleus of infected cells, with the envelopes of virions in the process of being occluded and fully occluded virions. First appears after 18 hours of infection. A microRNA encoded by the virus, AcMNPV-miR-1, matches the E25 gene and down-regulates its mRNA expression which presumably favors occlusion-derived virions over budded virions. Belongs to the baculoviridae p25 family.