Expression in a recombinant murid herpesvirus 4 reveals the in vivo transforming potential of the K1 open reading frame of Kaposi's sarcoma-associated herpesvirus.
Murid herpesvirus 4 (commonly called MHV-68) is closely related to Kaposi's sarcoma-associated herpesvirus (KSHV) and provides an excellent model system for investigating gammaherpesvirus-associated pathogenesis. MHV-76 is a naturally occurring deletion mutant of MHV-68 that lacks 9,538 bp of the left end of the unique portion of the genome encoding nonessential pathogenesis-related genes. The KSHV K1 protein has been shown to transform rodent fibroblasts in vitro and common marmoset T lymphocytes in vivo. Using homologous recombination techniques, we successfully generated recombinants of MHV-76 that encode green fluorescent protein (MHV76-GFP) and KSHV K1 (MHV76-K1). The replication of MHV76-GFP and MHV76-K1 in cell culture was identical to that of MHV-76. However, infection of BALB/c mice via the intranasal route revealed that MHV76-K1 replicated to a 10-fold higher titer than MHV76-GFP in the lungs at day 5 postinfection (p.i.). We observed type 2 pneumocyte proliferation in areas of consolidation and interstitial inflammation of mice infected with MHV76-K1 at day 10 p.i. MHV76-K1 established a 2- to 3-fold higher latent viral load than MHV76-GFP in the spleens of infected mice on days 10 and 14 p.i., although this was 10-fold lower than that established by wild-type MHV-76. A salivary gland tumor was present in one of four mice infected with MHV76-K1, as well as an increased inflammatory response in the lungs at day 120 p.i. compared with that of mice infected with MHV-76 and MHV76-GFP.
Douglas
Jill
J
Centre for Infectious Diseases, University of Edinburgh, Summerhall, Edinburgh EH9 1QH, United Kingdom.
Dutia
Bernadette
B
Rhind
Susan
S
Stewart
James P
JP
Talbot
Simon J
SJ
D000818:Animals; D002460:Cell Line; D002472:Cell Transformation, Viral; D006224:Cricetinae; D004195:Disease Models, Animal; D005260:Female; D049452:Green Fluorescent Proteins; D019288:Herpesvirus 8, Human / Q000472:pathogenicity*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D016366:Open Reading Frames / Q000235:genetics / Q000502:physiology*; D011995:Recombination, Genetic; D018144:Rhadinovirus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
C111600:K1 protein, Human herpesvirus 8; D008164:Luminescent Proteins; D014764:Viral Proteins; D049452:Green Fluorescent Proteins