Previous Article | Next Article ![]()
J. Virol., 06 1997, 4385-4394, Vol 71, No. 6
RS Weiss, MO Gold, H Vogel and RT Javier
Human adenovirus type 9 (Ad9) elicits exclusively estrogen-dependent
mammary tumors in rats, and an essential oncogenic determinant for this
virus is Ad9 E4 open reading frame 1 (9ORF1), which encodes a 125- residue
cytoplasmic protein with cellular growth-transforming activity in vitro. In
this study, we engineered 48 different mutant 9ORF1 genes in an attempt to
identify regions of this viral protein essential for transformation of the
established rat embryo fibroblast cell line CREF. In initial assays with
CREF cells, 17 of the 48 mutant 9ORF1 genes proved to be severely defective
for generating transformed foci but only 7 of these defective genes
expressed detectable amounts of protein. To further examine the defects of
the seven mutant proteins, we selected individual cell pools of stable CREF
transformants for the wild-type and mutant 9ORF1 genes. Compared to cell
pools expressing the wild-type 9ORF1 protein, most cell pools expressing
mutant proteins displayed decreased growth in soft agar, and all generated
significantly smaller tumors in syngeneic animals. The altered amino acid
residues of the seven mutant 9ORF1 polypeptides clustered within three
separate regions referred to as region I (residues 34 to 41), region II
(residues 89 to 91), and C-terminal region III (residues 122 to 125). By
using indirect immunofluorescence, we also assessed whether the mutant
proteins localized properly to the cytoplasm of cells. The region I and
region II mutants displayed approximately wild-type subcellular
localizations, whereas most region III mutants aberrantly accumulated
within the nucleus of cells. In summary, we have identified three 9ORF1
protein regions necessary for cellular transformation and have demonstrated
that C-terminal region III sequences significantly influence the proper
localization of the 9ORF1 polypeptide in cells.
Copyright © 1997, American Society for Microbiology
Mutant adenovirus type 9 E4 ORF1 genes define three protein regions required for transformation of CREF cells
Division of Molecular Virology, Baylor College of Medicine, Houston, Texas 77030, USA.
This article has been cited by other articles:
| J. Bacteriol. | Mol. Cell. Biol. | Microbiol. Mol. Biol. Rev. |
|---|
| Clin. Vaccine Immunol. | ALL ASM JOURNALS |
|---|