p53-dependent apoptosis is regulated by a C-terminally alternatively spliced form of murine p53.
It is now well accepted that the p53 C-terminus plays a central role in controlling the activity of the wild-type molecule. In our previous studies, we observed that a C-terminally altered p53 protein (p53AS), generated by an alternative spliced p53 mRNA, induces an attenuated p53-dependent apoptosis, compared to that induced by the regularly spliced form (p53RS). In the present study we analysed the interrelationships between these two physiological variants of wild-type p53, and found that in cells co-expressing both forms, in contrast to the expected additive effect on the induction of apoptosis, p53AS inhibits apoptosis induced by p53RS. This inhibitory effect is specific for p53-dependent apoptosis and was not evident in a p53-independent apoptotic pathway induced by growth factor deprivation. Furthermore, the expression of p53AS in transiently transfected cells caused both inhibition of apoptosis and inhibition of the p53RS-dependent transactivation of a number of p53 target genes. These results suggest that expression of an alternatively spliced p53 form may serve as an additional level in controlling the complexity of p53 function by the C-terminal domain.
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel.
N
N
Almog
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N
Goldfinger
V
V
Rotter
D017398:Alternative Splicing; D000818:Animals; D017209:Apoptosis; D056746:Cyclin G; D056766:Cyclin G1; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D051028:bcl-2-Associated X Protein
C534702:CCNG1 protein, human; C493956:CDKN1A protein, human; C534703:Ccng1 protein, mouse; C493957:Cdkn1a protein, mouse; D056746:Cyclin G; D056766:Cyclin G1; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D020033:Protein Isoforms; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein