Two distinct mechanisms regulate the levels of a cellular tumor antigen, p53.

摘要: The steady-state levels of p53 protein and mRNA in transformed nontransformed cells were examined to elucidate the mechanisms controlling expression p53. determined by Northern blot hybridization analysis, employing a p53-specific cDNA clone (M. Oren A.J. Levine, Proc. Natl. Acad. Sci. U.S.A. 80:56-59, 1983), Western blotting technique. Analysis revealed single polyadenylated species migrating at ca. 18S. Levels simian virus 40-transformed cell line (SVT2) an homologous (3T3) equivalent, although 25- 100-fold higher SVT2 than 3T3 cells. A study with non-virus-transformed system different result. Embryonal carcinoma (F9) found have nearly 20-fold comparison differentiated benign progeny In this difference corresponded levels. Pulse-chase experiments performed half-life these four types turnover occurred biphasic kinetics. addition, it was that synthesis inhibitors placed medium during chase period prevented cells, but not These results provide evidence regulation can occur level abundancy or stability depending upon experimental under study, regulated degradation process controls protein.