@article{oai:sapmed.repo.nii.ac.jp:00014219,
 author = {Kimura, KagiichiSachiko and Yamashita, Toshiharu and Yoshida, Koichi and Ishidal, Setsuko and Mori, Michio and Fujinaga, Kei},
 journal = {Tumor Research, Tumor Research},
 month = {},
 note = {Primary baby rat kidney (BRK) cells were transfected with two different non-immortalizing mutants of adenovirus type 5 (Ad5) E1A(s) and/or human papillomavirus type 16 (HPV16) E7(s) to test whether immortalization was induced by the genetic complementation. Co-transfection of an RB-nonbinding E1A mutant (d1922/947) and N-terminal E7 mutant (2PRO) formed transformed foci on BRK cells, but a combination of an N-terminal E1A mutant (NTdl598) and RB-nonbinding E7 mutant (24GLY) did not. However, NTd1598 plus 24GLY as well as dl922/947 plus 2PRO produced immortalized BRK cell lines. The cell lines immortalized by dl922/947 plus 2PRO showed a morphology similar to those immortalized by Ad5 E1A ; while cell lines immortalized by NTdl598 plus 24GLY showed a morphology similar to those immortalized by HPV16 E7. These results suggest that the RB-binding regions of Ad5 E1A and HPV16 E7 are mutually replaceable, and that the N-terminal function of E1A is essential for focus formation and maintenance of transformation morphology. A combination of RB-nonbinding mutants, E1A dl922/947 plus E7 24GLY, was able to immortalize BRK cells when introduced together with the Ad5 E1B 19K gene. The Ad5 E1B 55K and Bcl-2, which also possess anti-apoptotic activity, did not increase colony formation of and/or immortalize BRK cells when co-transfected with dl922/947 plus 24GLY. In a CAT assay E1B 19K, but not Bc1-2, enhanced E2F-dependent CAT transactivation by Ad5 ElA or dl922/947. Thus, it is suggested that E1B 19K might complement RB-nonbinding mutants by means of two activities, suppression of apoptosis and enhancement of E2F-dependent transactivation.},
 pages = {1--21},
 title = {Immortalization of Primary Rat Cells by Reciprocal Complementations of Human Papillomavirus Type 16 E7 and Adenovirus Type 5 E1A Mutants},
 volume = {32},
 year = {1997}
}