title: p53 protein subcellular localization and apoptosis in rodent corneal             epithelium cell culture following ultraviolet irradiation.
abstract: The tumor-suppressor gene p53 encodes a phosphoprotein involved in the control             of cell growth. p53 expression and function have been documented in malignancy,             apoptosis and the aging processes. Recently, p53 has been mapped and characterized             in the normal cornea across different species. In the present study, high levels             of cytoplasmic p53 protein were noted in normal primary corneal epithelium cultures             by immunohistochemistry and western blot analysis. Following ultraviolet (UV)             irradiation, the level of cytoplasmic p53 protein expression was increased beginning             from 30 min and lasting until 6 h post-irradiation and then returned close to             control levels by 24 h. Cytoplasmic p53 phosphorylation was detected from 30 min             following UV treatment until 6 h post-irradiation. p53 protein became apparent             in the nucleus in a fraction of these cultured cells beginning 30 min following             UV irradiation and was still present 24 h later. We also found that p53 colocalized             with mitochondria 2 h following UV irradiation in some of the cells and remained             there up to 24 h. As the expression levels of p53 transcription following UV irradiation             were not significantly altered, the increase in cytoplasmic p53 protein expression             may be conditional only upon post-translational stabilization. We also observed             that the apoptotic index increased following UV irradiation in the same time frame             as the p53 nuclear transfer and was partially suppressed by pifithrin-α, which             is a reversible inhibitor of p53-mediated apoptosis and p53-dependent gene transcription.             The present study offers new evidence suggesting that cytoplasmic p53 in rodent             corneal epithelium is functionally active.
authors: Department of Clinical Biochemistry, Rambam Medical Center, Haifa, Israel. tendler@tx.technion.ac.il
authors: Yevgeny
authors: Y
authors: Tendler
authors: Russell
authors: R
authors: Pokroy
authors: Alex
authors: A
authors: Panshin
authors: Gary
authors: G
authors: Weisinger
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects*; D052160:Benzothiazoles / Q000494:pharmacology; D002478:Cells, Cultured; D019573:Epithelium, Corneal / Q000378:metabolism / Q000528:radiation effects*; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000032:analysis; D014050:Toluene / Q000031:analogs & derivatives / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D000911:Antibodies, Monoclonal; D052160:Benzothiazoles; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; D014050:Toluene; C121565:pifithrin