TRANSDOMINANT INTERFERENCE OF TYPE-5 ADENOVIRUS E1A MUTANTS IN CELL-TRANSFORMATION

Two type 5 adenovirus (Ad5) early region 1a (E1a) mutants, H5in104 and H5dl105, were impaired in viral replication and cell transformation. In addition, these mutants trans dominantly inhibited the frequency wi th which H5sub309, a phenotypically wild-type mutant, and H5dl520, a h igh-frequency transformation mutant, transformed CREF cells. Inhibitio n of transformation varied in proportion to the input ratio of mutant to coinfecting virus. It was found that H5in104, but not H5dl105, coul d not complement Ad5 E1b mutants that failed to synthesize 19- or 55-k Da E1b product. H5dl105 yielded 10-fold less virus than the wild-type did in 293 cells, which constitutively express E1a and E1b products; s imilar low yields were also observed with H5in104? and H5dl105 in anot her E1a- and E1b-expressing transformed cell line, KB16. Marker rescue and DNA sequence analyses, however, indicated that the phenotypes of H5in104 and H5dl105 were the result of their respective E1a mutations. The data presented are the first to demonstrate that mutants of anima l viruses can effect dominant interference with the viral function(s) that produce cell transformation.