Sequence and temporal appearance of the early transcribed baculovirus gene HE65

Abstract

We have identified the early transcribed HE65 gene by screening a cDNA library from polyadenylated RNA which was isolated at 1 h after infection of Spodoptera frugiperda cells with Autographa californica nuclear polyhedrosis virus (AcNPV). Nucleotide sequencing analysis of the HE65-specific cDNA clone reveals one open reading frame of 1,662 nucleotides from which a protein of 65 kDa in size can be predicted. The HE65 gene is located downstream of the late transcribed p80 gene and upstream of the homologous region hr4left, which overlaps the 5' sequences of the HE65 gene. An HE65-specific transcript of about 1,800 nucleotides is detectable 2 h postinfection and remains stable during the late phases of infection. RNase protection and primer extension analyses demonstrate that transcripts from the early start site of HE65 continue to accumulate from 2 to 48 h postinfection, even in the presence of aphidicolin. Furthermore, transcriptional analysis of the HE65 gene indicates a lower intensity of early transcription in comparison with the very early transcribed genes IEN, PE38, and ME53.