Identification, sequence analysis, and phylogeny of the immediate early gene 1 of the Trichoplusia ni single nucleocapsid polyhedrosis virus.
Substantial research has been conducted on the immediate early I (ie-1) genes from the prototype baculovirus Auographa californica multicapsid nuclear polyhedrosis virus (AcMNPV) and the Orgyia pseudotsugata multicapsid nuclear polyhedrosis virus (OpMNPV). In both cases ie-1 gene products have been implicated in transcriptional activation and repression. In this study an ie-1 homolog was identified from Trichoplusia ni single nucleocapsid polyhedrosis virus (TniSNPV). Nucleotide sequence analysis indicated that the TniSNPV ie-1 gene consists of a 2,217 nucleotide open reading frame (ORF), encoding a protein with a molecular mass of 84.464 kDa. This represents the largest baculovirus ie-1 gene characterised to date. Of the seven ie-1 homologs identified to date, the TniSNPV ie-1 shared most sequence similarity with the ie-1 gene of Spodoptera exigua MNPV (SeMNPV) (41%). At the nucleotide level, expected TATA and CAGT motifs were found to precede each ie-1 ORE. At the protein level, it was confirmed that the N-termini are poorly conserved, but share the characteristic of having a high proportion of acidic amino acids. In addition it was found that N-terminal regions significantly matched the SET domain in the Swiss-Prot prosite database. The C-terminal regions of the deduced IE-1 sequences were found to be substantially more conserved than the N-termini. Several conserved motifs were identified in the C-terminal sequences. A phylogenetic tree of nine baculovirus IE-1 proteins was constructed using maximum parsimony analysis. The phylogenetic estimation of the ie-1 genes shows that TniSNPV is a member of the previously described lepidopteran NPV group II and it is most closely related to SeMNPV.
Wang
W
W
Department of Microbiology, University of the Western Cape, Bellville, South Africa.
Leat
N
N
Fielding
B
B
Davison
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004279:DNA, Viral; D004268:DNA-Binding Proteins / Q000145:classification / Q000235:genetics*; D017781:Genes, Immediate-Early; D005814:Genes, Viral; D017874:Immediate-Early Proteins / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D009036:Moths / Q000821:virology*; D019251:Nucleocapsid; D017924:Nucleopolyhedroviruses / Q000235:genetics*; D016366:Open Reading Frames; D010802:Phylogeny; D012045:Regulatory Sequences, Nucleic Acid; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D015534:Trans-Activators / Q000145:classification / Q000235:genetics*; D014764:Viral Proteins / Q000145:classification / Q000235:genetics*
C069183:Ac-IE-1 protein, Autographa californica nucleopolyhedrovirus; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D017874:Immediate-Early Proteins; D015534:Trans-Activators; D014764:Viral Proteins