title: Identification and functional analysis of a putative non-hr origin of DNA replication from the Spodoptera littoralis type B multinucleocapsid nucleopolyhedrovirus.
abstract: A putative non-hr origin of DNA replication was identified in the Spodoptera littoralis multinucleocapsid nucleopolyhedrovirus (SpliNPV) genome by transient replication assays. The putative SpliNPV ori was mapped to the PstI-J fragment between 75.1-77.9 map units in the SpliNPV genome. While the DNA sequence of the putative SpliNPV ori aligned with regions within the non-hr oris of Autographa californica, Orgyia pseudotsugata and Spodoptera exigua multinucleocapsid nucleopolyhedroviruses, it has limited DNA sequence identity with these elements. The sequence of the putative SpliNPV non-hr ori fragment contains a unique distribution of imperfect palindromes, multiple direct repeats and putative transcription factor-binding sites. Transient expression assays indicated that the putative SpliNPV ori fragment repressed SpliNPV lef-3 promoter-mediated luciferase reporter gene expression. However, the putative SpliNPV ori fragment itself was capable of directing luciferase expression in the absence of a recognizable baculovirus promoter element in an orientation-independent fashion, suggesting that DNA sequence motifs within its sequence can activate transcription. Gel mobility shift analyses confirmed that proteins within nuclear extracts from both uninfected and virus-infected cells bound with specificity to the putative SpliNPV ori fragment.
authors.affiliation: Department of Biology, University of Victoria, PO Box 3020, Victoria, British Columbia, Canada V8W 3N51.
authors.forename: Jianhe
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Biology, University of Victoria, PO Box 3020, Victoria, British Columbia, Canada V8W 3N51.
authors.forename: David B
authors.initials: DB
authors.lastname: Levin
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004261:DNA Replication; D004279:DNA, Viral; D004268:DNA-Binding Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000235:genetics*; D018741:Replication Origin / Q000502:physiology*; D017422:Sequence Analysis, DNA; D018411:Spodoptera / Q000821:virology
chemical_list: D004279:DNA, Viral; D004268:DNA-Binding Proteins