Identification and characterization of Hyphantria cunea nucleopolyhedrovirus homologous repeated regions.
A total of six homologous regions (hycu-hrs1-6) were identified in the genome of Hyphantria cunea nucleopolyhedrovirus (HycuNPV). These hycu-hrs were localized in non-coding regions interspersed throughout the HycuNPV genome and showed structural homology to several other baculovirus hrs. Sequence analyses indicated that hycu-hrs were composed of 65-69-bp direct repeats, each of which contained a 29-31-bp imperfect palindrome embedded within non-palindromes tandemly arranged. hycu-hrs consisted of a variable number of repeats ranging from two for hycu-hr3 to twenty-five for hycu-hr6, and these repeats showed a high degree of identity to each other. The hycu-hr6, which was localized immediately upstream of HycuNPV gp64 gene (hycu-gp64), represented the longest hr among group I NPV hrs reported to date. Transient expression assays demonstrated that the expression of hycu-gp64 promoter-driven luciferase gene (luc) was dramatically enhanced by hycu-hr6 which was placed upstream and downstream of luc in an orientation-independent manner. Moreover, hycu-hr6-dependent enhancement was observed in the absence of any additional viral gene products, although it could be further strengthened in the presence of HycuNPV ie-1 gene product. These results indicate that hycu-hrs function as enhancers of transcription mediated by RNA polymerase II, and suggest for the first time that efficiency of gp64 promoter is dependent on the enhancement function of hrs.
Alves
Cristiano A Felipe
CA
Laboratory of Biodynamics, Graduate School of Bioagricultural Sciences, Nagoya University, 464-8601, Chikusa, Nagoya, Japan.
Ikeda
Motoko
M
Kobayashi
Michihiro
M
D000818:Animals; D001483:Base Sequence; D004279:DNA, Viral / Q000235:genetics*; D008969:Molecular Sequence Data; D009036:Moths / Q000821:virology*; D017924:Nucleopolyhedroviruses / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D017385:Sequence Homology
D004279:DNA, Viral