Identification and characterization of the Spodoptera littoralis nucleopolyhedrovirus type B lef-3 gene.
We have identified a gene from the Spodoptera littoralis nucleopolyhedrovirus type B (SpliNPV-B) with several characteristics that suggest that it is homologous to the lef-3 genes of the Autographa californica and Orgyia pseudotsugata NPVs (AcMNPV and OpMNPV, respectively). The SpliNPV-B lef-3 gene was mapped between 43.6 and 45.5 map units of the SpliNPV-B genome. Northern blot analysis showed that SpliNPV-B lef-3 was expressed as a 1.6 Kb transcript at 5 h post infection (p.i.), reached high levels at 24 h p.i., and remained highly expressed at 56 h p.i. Transcription of SpliNPV-B lef-3 initiated at two distinct sites downstream from a TATA-box motif and terminated 25 nucleotides downstream from the translation stop site of the putative LEF-3 polypeptide. The 5'-boundaries of lef-3 promoter elements were investigated by transient expression assays, which revealed that the major components of the lef-3 promoter are within a 183 base pair region upstream of the distal transcription initiation site. Transfection of SpliNPV-B infected Sf9 cells with anti-sense oligonucleotides designed to inhibit LEF-3 expression resulted in substantial reduction of viral DNA replication, suggesting that the role of SpliNPV-B lef-3 may be similar to that of AcMNPV and OpMNPV lef-3 genes, which are essential for viral DNA replication.
Wolff
J L
JL
Department of Biology, University of Victoria, Canada.
Herzog
L M
LM
Sun
L
L
Levin
D B
DB
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D001973:Bromodeoxyuridine / Q000378:metabolism; D002460:Cell Line; D002874:Chromosome Mapping; D018076:DNA, Complementary; D004279:DNA, Viral / Q000096:biosynthesis; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000502:physiology; D015870:Gene Expression; D005814:Genes, Viral; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000235:genetics* / Q000502:physiology; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D011401:Promoter Regions, Genetic; D016415:Sequence Alignment; D018411:Spodoptera / Q000821:virology; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000235:genetics* / Q000502:physiology; D014779:Virus Replication
D018076:DNA, Complementary; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D016376:Oligonucleotides, Antisense; D014764:Viral Proteins; C094647:late expression factor 3, baculovirus; D001973:Bromodeoxyuridine