Changes in c-Jun but not Bcl-2 family proteins in p53-dependent apoptosis of mouse cerebellar granule neurons induced by DNA damaging agent bleomycin.
Tumor suppressor gene p53 is a critical regulator of the cellular response to DNA damage. To examine the function of p53 in postmitotic CNS neurons, we cultured cerebellar granule cells from 15-day-old wild type and p53-deficient mice, and analyzed changes of protein expression in apoptosis elicited by DNA damage. When cerebellar granule cells from wild type mice were treated with bleomycin, a DNA strand-break inducing agent, neuronal death occurred. In contrast, cells from p53-deficient mice were resistant to bleomycin-induced neuronal death. Furthermore, cells from p53 heterozygous mice showed an intermediate resistance between wild type and p53-deficient mice. These results show that p53 is required for the bleomycin-induced cerebellar granule cell death. To examine which proteins are involved in this apoptosis, we examined changes in protein levels of the Bcl-2 family, including Bcl-2, Bcl-X and Bax. The relative amounts of these proteins did not change after bleomycin treatment, suggesting that the changes in the levels of these Bcl-2 family proteins are not necessary for apoptosis in this system. In contrast, the levels of c-Jun protein significantly increased 6 h after treatment with bleomycin in wild type but not in p53-deficient cerebellar granule cells. These results raise the possibility that c-Jun is required for p53-dependent neuronal apoptosis induced by bleomycin.
Araki
T
T
Division of Protein Biosynthesis, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565, Japan.
Enokido
Y
Y
Inamura
N
N
Aizawa
S
S
Reed
J C
JC
Hatanaka
H
H
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001761:Bleomycin / Q000633:toxicity*; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004249:DNA Damage; D016158:Genes, p53; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D016755:Proto-Oncogene Proteins c-jun / Q000096:biosynthesis; D051028:bcl-2-Associated X Protein
C494827:Bax protein, mouse; D009419:Nerve Tissue Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016755:Proto-Oncogene Proteins c-jun; D051028:bcl-2-Associated X Protein; D001761:Bleomycin