In vivo replication kinetics and transcription patterns of the nucleopolyhedrovirus (NeabNPV) of the balsam fir sawfly, Neodiprion abietis.
DNA replication and transcription of NeabNPV, the nucleopolyhedrovirus (NPV) of the balsam fir sawfly, Neodiprion abietis (Hymenoptera: Diprionidae), in host larvae were investigated. NPV DNA replication kinetics and gene-expression patterns have been resolved only in lepidopteran cell-culture systems and in limited in vivo experiments with lepidopteran larvae. Furthermore, there are significant differences in pathologies caused by lepidopteran NPVs, which replicate in many tissues, and hymenopteran NPVs, known to replicate in midgut epithelium only. Despite the differences in host specificity and pathology, NeabNPV DNA replication kinetics were similar to those reported for lepidopteran NPVs. Maximal NeabNPV DNA synthesis was observed between 4 and 24 h post-inoculation (p.i.) but, in contrast to lepidopteran NPVs, synthesis continued at a lower rate up to 72 h p.i. Selected NeabNPV genes exhibited a cascade pattern of transcription similar to that of lepidopteran NPVs. RT-PCR products of the NeabNPV lef-1, lef-2 and dnapol transcripts were observed as early as 2 h p.i., whilst lef-8 and lef-9, encoding putative viral RNA polymerase subunits, were detected at 1 and 6 h p.i., respectively. Two structural late transcripts (gp41 and p74) were observed from 6 h p.i. The very late factor 1 (vlf-1) transcript, a transactivator of very late genes, was observed from 12 h p.i., but the very late transcript polh, encoding the major occlusion protein, polyhedrin, was observed from 24 h p.i. This study provides the first insight into DNA replication and gene expression of a non-lepidopteran baculovirus.
Duffy
Simon P
SP
The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada.|Department of Biology, University of Victoria, Victoria, BC V8W 2Y2, Canada.
Becker
Elisa M
EM
Department of Biology, University of Victoria, Victoria, BC V8W 2Y2, Canada.
Whittome
Beatrixe H
BH
Department of Biology, University of Victoria, Victoria, BC V8W 2Y2, Canada.
Lucarotti
Christopher J
CJ
Canadian Forest Service - Atlantic Forestry Centre, PO Box 4000, Regent Street, Fredericton, NB E3B 5P7, Canada.
Levin
David B
DB
Department of Biosystems Engineering, E2-376 EITC, University of Manitoba, Winnipeg, MB R3T 5V6, Canada.|Department of Biology, University of Victoria, Victoria, BC V8W 2Y2, Canada.
D028202:Abies / Q000469:parasitology; D000818:Animals; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis / Q000235:genetics; D015967:Gene Expression Regulation, Viral; D006927:Hymenoptera / Q000821:virology*; D007700:Kinetics; D007814:Larva / Q000821:virology; D007915:Lepidoptera / Q000821:virology; D017924:Nucleopolyhedroviruses / Q000235:genetics* / Q000502:physiology*; D013045:Species Specificity; D014158:Transcription, Genetic; D014779:Virus Replication
D004279:DNA, Viral