Suppression of adenovirus E1A-induced apoptosis by mutated p53 is overcome by coexpression with Id proteins
AUTOR(ES)
Nakajima, Takuma
FONTE
The National Academy of Sciences
RESUMO
The rat 3Y1 derivative cell lines, EId10 and EId23, established by introducing the adenovirus E1A12S, Id-1H, and Id-2H cDNAs linked to the hormone-inducible promoter, express these proteins upon treatment with dexamethasone and elicit apoptosis, although these cell lines express mutated p53. The E1A mutants containing a deletion in either the N terminus or the conserved region 1 were unable to induce apoptosis in cooperation with Ids. Western blot analysis of the immunoprecipitates prepared from the dexamethasone-treated EId10 cell extract showed that Id-2H preferentially binds to E1A and E2A (E12/E47) helix–loop–helix transcription factors in vivo, but scarcely to the retinoblastoma protein. After induction of E1A and Ids, EId10 and EId23 cells began to accumulate in S phase and undergo apoptosis before entering G2 phase, suggesting that abnormal synthesis of DNA induced by coexpression of E1A, Id-1H, and Id-2H results in the induction of apoptosis. Apoptosis also is induced in mouse A40 (p53−/−) cells by E1A alone or E1A plus Ids after transient transfection of the expression vectors. The induction of apoptosis is stimulated by coexpression with wild-type p53; however, apoptosis induced by E1A alone was suppressed completely by coexpression with mutated p53, whereas apoptosis induced by E1A plus Ids was stimulated by the mutated p53 as done by wild-type p53. These results suggest that the suppressive function of mutated p53 is overcome by Ids.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=27939Documentos Relacionados
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