Analysis of the promoter of the Autographa californica nuclear polyhedrosis virus p10 gene.

Functional analyses of the p10 gene promoter from the Autographa californica nuclear polyhedrosis virus (AcNPV) were performed by progressively deleting the 230 nucleotides upstream from the p10 coding sequences towards the ATG codon. Truncated promoter sequences retaining the full 5' non-coding leader of p10 were inserted in front of the chloramphenicol acetyltransferase (CAT) gene, and promoter activity in transfected AcNPV-infected cells was measured using the transient CAT expression assay. The removal of sequences to a position 101 nucleotides upstream from the p10 ATG did not affect the level of CAT expression. Deletion of a further 13 nucleotides reduced CAT expression by three- to fourfold, but the removal of three more nucleotides, which deleted most of the baculovirus very late gene transcription consensus sequence, almost completely abolished activity. The removal of the TATA motif had no effect on the level of transient expression. We conclude that a sequence of about 101 nucleotides upstream from the ATG codon of p10 is sufficient for high level promoter activity in this transient system.