Identification and transcriptional regulation of the baculovirus lef-6 gene.

We identified an Autographa californica nuclear polyhedrosis virus (AcMNPV) gene, the late expression factor 6 gene (lef-6), which is involved in expression from late and very late AcMNPV gene promoters but not from an early AcMNPV gene promoter in transient expression assays. This gene was located within the PstI I fragment of the AcMNPV genome (14.7 to 17.9 map units), immediately downstream of Ac-iap, the AcMNPV homolog of a baculovirus gene family involved in blocking apoptotic programmed cell death. The nature and temporal regulation of both Ac-iap and lef-6 transcripts was examined. Ac-iap and lef-6 were cotranscribed as bicistronic messages at both early and late times postinfection. In addition, lef-6 was transcribed as a monocistronic mRNA by initiation from an early promoter within Ac-iap.