title: Accumulation of wild-type p53 protein upon gamma-irradiation induces a G2 arrest-dependent immunoglobulin kappa light chain gene expression.
abstract: The exposure of cells to DNA-damaging agents leads to the accumulation of wild-type p53 protein. Furthermore, overexpression of the wild-type p53, mediated by transfection of p53-coding cDNA, induced cells to undergo apoptosis or cell differentiation. In this study we found that the gamma-irradiation that caused the accumulation of wild-type p53 in 70Z/3 pre-B cells induced, in addition to apoptosis, cell differentiation. This was manifested by the expression of the kappa light chain immunoglobulin gene that coincided with the accumulation of cells at the G2 phase. Overexpression of mutant p53 in 70Z/3 cells interferes with both differentiation and accumulation of cells at the G2 phase, as well as with apoptosis, which were induced by gamma-irradiation. Furthermore, the increment in the wild-type p53 protein level following gamma-irradiation was disrupted in the mutant p53 overproducer-derived cell lines. This suggests that mutant p53 may exert a dominant negative effect in all of these activities. Data presented here show that while p53-induced apoptosis is associated with the G1 checkpoint, p53-mediated differentiation, which may be an additional pathway to escape the fixation of genetic errors, may be associated with the G2 growth arrest phase.
authors.affiliation: Department of Cell Biology, The Weizmann Institute of Science, Rehovot, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Aloni-Grinstein
authors.forename: D
authors.initials: D
authors.lastname: Schwartz
authors.forename: V
authors.initials: V
authors.lastname: Rotter
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D017209:Apoptosis / Q000528:radiation effects; D001402:B-Lymphocytes / Q000276:immunology / Q000502:physiology / Q000528:radiation effects; D001483:Base Sequence; D015153:Blotting, Western; D002453:Cell Cycle / Q000502:physiology / Q000528:radiation effects; D002460:Cell Line; D017931:DNA Primers; D004307:Dose-Response Relationship, Radiation; D005434:Flow Cytometry; D016195:G2 Phase / Q000502:physiology / Q000528:radiation effects; D005720:Gamma Rays; D015870:Gene Expression / Q000502:physiology* / Q000528:radiation effects; D005803:Genes, Immunoglobulin / Q000528:radiation effects*; D016158:Genes, p53 / Q000528:radiation effects*; D007145:Immunoglobulin kappa-Chains / Q000096:biosynthesis*; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D016159:Tumor Suppressor Protein p53 / Q000032:analysis / Q000096:biosynthesis*
chemical_list: D000911:Antibodies, Monoclonal; D017931:DNA Primers; D007145:Immunoglobulin kappa-Chains; D016159:Tumor Suppressor Protein p53