A replication-competent feline leukemia virus, subgroup A (FeLV-A), tagged with green fluorescent protein reporter exhibits in vitro biological properties similar to those of the parental FeLV-A.
We previously established that lymphoid tumors could be induced in cats by intradermal injection of ecotropic feline leukemia virus (FeLV), subgroup A, plasmid DNA. In preparation for in vivo experiments to study the cell-to-cell pathway for the spread of the virus from the site of inoculation, the green fluorescent protein (GFP) transgene fused to an internal ribosome entry site (IRES) was inserted after the last nucleotide of the env gene in the ecotropic FeLV-A Rickard (FRA) provirus. The engineered plasmid was transfected into feline fibroblast cells for production of viruses and determination of GFP expression. The virions produced were highly infectious, and the infected cells could continue to mediate strong expression of GFP after long-term propagation in culture. Similar to parental virus, the transgene-containing ecotropic virus demonstrated recombinogenic activity with endogenous FeLV sequences in feline cells to produce polytropic recombinant FeLV subgroup B-like viruses which also contained the IRES-GFP transgene in the majority of recombinants. To date, the engineered virus has been propagated in cell culture for up to 8 months without diminished GFP expression. This is the first report of a replication-competent FeLV vector with high-level and stable expression of a transgene.
Chang
Z
Z
Department of Pathology, University of Southern California School of Medicine, Los Angeles, California 90033, USA.
Pan
J
J
Logg
C
C
Kasahara
N
N
Roy-Burman
P
P
D000595:Amino Acid Sequence; D000818:Animals; D002415:Cats; D002460:Cell Line; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D005256:Leukemia Virus, Feline / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015682:Retroviridae Proteins, Oncogenic / Q000235:genetics / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication
D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D015682:Retroviridae Proteins, Oncogenic; D014759:Viral Envelope Proteins; C051525:feline leukemia virus protein p15E; C073723:glycoprotein gp70, Feline leukemia virus; D049452:Green Fluorescent Proteins