Molecular analysis of a baculovirus regulatory gene.
To better understand the structure and function of a baculovirus regulatory gene, the nucleotide sequence of IE-N expressed by Autographa californica nuclear polyhedrosis virus was determined. The 2.0-kb PstI-EcoRV restriction fragment (97.5 to 98.9 mu) encodes the upstream regulatory sequences, open reading frame, and downstream sequences of the immediate early IE-N gene. Using a convenient restriction site, the 285-bp promoter of IE-N was divided into two functional regions as defined by transient expression assays of mutant sequences. The sequences of IE-N from -1 to -45 nt encoded a minimal promoter capable of directing low levels of transcription. The minimal promoter was fully responsive to positive regulation by IE-N. The upstream region from -46 to -285 nt contains two direct repeats which increased levels of IE-N gene expression. Computer-assisted translation of the IE-N sequence indicates that this fragment of DNA encodes a single long open reading frame with a predicted molecular weight of 47,000. The amino acid sequence of the predicted protein exhibits three motifs common to transcriptional regulators: a serine-threonine rich region, a proline-rich region, and a polyglutamine tract. IE-N autoregulates its own expression and stimulates both IE-1 and IE-0 in transient assays. The stimulation of IE-1 may account for the augmenting activity of IE-N in the IE-1-mediated trans-activation of the 39K promoter.
Carson
D D
DD
Departments of Biochemistry & Biophysics, Texas A&M University, College Station 77843.
Summers
M D
MD
Guarino
L A
LA
D000595:Amino Acid Sequence; D016367:Baculoviridae / Q000235:genetics*; D001483:Base Sequence; D004252:DNA Mutational Analysis; D004279:DNA, Viral / Q000235:genetics; D004268:DNA-Binding Proteins; D015967:Gene Expression Regulation, Viral; D005809:Genes, Regulator; D005814:Genes, Viral; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000737:chemistry; D011401:Promoter Regions, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D015534:Trans-Activators / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics; D015678:Viral Structural Proteins / Q000235:genetics*
D004279:DNA, Viral; D004268:DNA-Binding Proteins; D009841:Oligonucleotides; D015534:Trans-Activators; D014764:Viral Proteins; D015678:Viral Structural Proteins; C068649:Ac-IE-2 protein, Autographa californica nucleopolyhedrovirus