Molecular analysis of the trans-activating IE-2 gene of Orgyia pseudotsugata multicapsid nuclear polyhedrosis virus.
A second immediate early (IE) regulatory gene of the baculovirus Orgyia pseudotsugata multicapsid nuclear polyhedrosis virus (OpMNPV) has been identified. The IE-2 gene which is homologous to the IE-N gene of Autographa californica MNPV was mapped to the HindIII A fragment of OpMNPV between 0.41 to 1.37 map units. The IE-2 gene codes for a predicted protein of 45,640 Da and analysis of the amino acid sequence shows that the protein has a highly basic amino terminal domain and a cysteine-rich domain that is similar to a zinc finger motif that is also found in the baculovirus proteins GC30 and PE-38. The IE-2 gene is expressed as a 1.3-kb transcript that was detectable by 0.5 hr postinfection (hr p.i.), reached maximum steady state levels by 6 hr p.i., and declined slightly by 48 hr p.i. Cis-acting 5' regulatory sequences were analyzed by deletion analysis of the IE-2 promoter linked to the reporter gene chloramphenicol acetyl transferase. Maximum expression was obtained when the IE-2 promoter contained sequence 275 bp upstream from the transcriptional start site. trans-Activation analysis revealed that IE-2 trans-activated the IE-1 promoter and in addition appeared to be autoregulatory.
Theilmann
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Agriculture Canada Research Station, Vancouver, British Columbia.
Stewart
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D000595:Amino Acid Sequence; D000818:Animals; D016367:Baculoviridae / Q000235:genetics*; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002460:Cell Line; D003001:Cloning, Molecular; D005809:Genes, Regulator; D017874:Immediate-Early Proteins; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D015534:Trans-Activators / Q000235:genetics*; D015533:Transcriptional Activation; D014764:Viral Proteins / Q000235:genetics*
D017874:Immediate-Early Proteins; D015534:Trans-Activators; D014764:Viral Proteins; C072773:IE2 protein, polyhedrosis virus