Functional characterization of Bombyx mori nucleopolyhedrovirus late gene transcription and genome replication factors in the non-permissive insect cell line SF-21.
We compared the abilities of late gene transcription and DNA replication machineries of the baculoviruses Autographa californica nucleopolyhedrovirus (AcMNPV) and Bombyx mori NPV (BmNPV) in SF-21 cells, an insect-derived cell line permissive for AcMNPV infection. It has been well established that 19 AcMNPV late expression factors (lefs) stimulate substantial levels of late gene promoter activity in SF-21 cells. Thus, we constructed a set of clones containing the BmNPV homologs of the AcMNPV lefs under control of the constitutive Drosophila heat shock 70 protein promoter and tested their ability to activate an AcMNPV late promoter-reporter gene cassette in SF-21 cells. We tested the potential of individual or predicted functional groups of BmNPV lefs to successfully replace the corresponding AcMNPV gene(s) in transient late gene expression assays. We found that most, but not all, BmNPV lefs were able to either fully or partially substitute for the corresponding AcMNPV homolog in the context of the remaining AcMNPV lefs with the exception of BmNPV p143, ie-2, and p35. BmNPV p143 was unable to support late gene expression or be imported into the nucleus of cells in the presence of the AcMNPV or the BmNPV LEF-3, a P143 nuclear shuttling factor. Our results suggest that host-specific factors may affect the function of homologous proteins.
Berretta
Marcelo F
MF
Division of Biology, Molecular, Cellular, and Developmental Biology Program, Kansas State University, 232 Ackert Hall, Manhattan, KS 66506-4901, USA.
Deshpande
Mandar
M
Crouch
Erin A
EA
Passarelli
A Lorena
AL
D000818:Animals; D019677:Artificial Gene Fusion; D002460:Cell Line; D002467:Cell Nucleus / Q000737:chemistry; D015500:Chloramphenicol O-Acetyltransferase / Q000032:analysis / Q000235:genetics; D004330:Drosophila / Q000235:genetics; D017930:Genes, Reporter; D005816:Genetic Complementation Test; D016679:Genome, Viral; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D017874:Immediate-Early Proteins / Q000235:genetics / Q000502:physiology; D015151:Immunoblotting; D008156:Luciferases / Q000032:analysis / Q000235:genetics; D008856:Microscopy, Fluorescence; D009036:Moths / Q000821:virology*; D017924:Nucleopolyhedroviruses / Q000235:genetics*; D011401:Promoter Regions, Genetic; D021381:Protein Transport; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000235:genetics / Q000502:physiology*; D014779:Virus Replication / Q000235:genetics*
D018840:HSP70 Heat-Shock Proteins; D017874:Immediate-Early Proteins; D015534:Trans-Activators; D014764:Viral Proteins; C081618:p35 protein, Nucleopolyhedrovirus; C072773:IE2 protein, polyhedrosis virus; D008156:Luciferases; D015500:Chloramphenicol O-Acetyltransferase