GENE-EXPRESSION BY ATYPICAL RECOMBINANT OVINE ADENOVIRUS VECTORS DURING ABORTIVE INFECTION OF HUMAN AND ANIMAL-CELLS IN-VITRO

An ovine adenovirus, which is phylogenetically distinct from the Masta deno- and Aviadenoviruses, was used to construct recombinants in which reporter genes were expressed from the OAV major late, or human cytom egalovirus promoters. It was demonstrated by transgene expression that OAV could infect bovine nasal turbinate and rabbit kidney cells as we ll as a range of human cell types, including lung and foreskin fibrobl asts as well as liver, prostate, breast, colon, and retinal lines. Som e human lines, e.g., 293 and LNCaP were not detectably infected. Infec tion occurred even though OAV has a fiber protein with a unique cell b inding domain and a penton protein that lacks the integrin-binding Arg -Gly-Asp motif which facilitates entry by human adenoviruses. Most cel l lines showed little or no ill effect for several days after infectio n but a prominent cytopathic effect appeared in fibroblasts after 3-4 days. However, no viral DNA synthesis was detected and replication was abortive. Viral promoter activity during infection of nonpermissive c ell types was assayed by RT-PCR. Early promoter activity was delectabl e in some, but not ail cell types. In a liver and a colon carcinoma ce ll line, none of the promoters examined was significantly active, even when a higher multiplicity of infection was used. Major late promoter activity was not detectable in any cell type. The lack oi DNA replica tion and MLP function suggests that a critical transition from early t o late gene expression does not occur during abortive infection by OAV . (C) 1997 Academic Press.