Thymocyte apoptosis induced by p53-dependent and independent pathways
| Autor: | Alan Richard Clarke, David J. Harrison, Colin A. Purdie, R. G. Morris, Colin C. Bird, Martin L. Hooper, Andrew H. Wyllie |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Nature. 362:849-852 |
| ISSN: | 1476-4687 0028-0836 |
| Popis: | Death by apoptosis is characteristic of cells undergoing deletion during embryonic development, T- and B-cell maturation and endocrine-induced atrophy. Apoptosis can be initiated by various agents and may be a result of expression of the oncosuppressor gene p53 (refs 6-8). Here we study the dependence of apoptosis on p53 expression in cells from the thymus cortex. Short-term thymocyte cultures were prepared from mice constitutively heterozygous or homozygous for a deletion in the p53 gene introduced into the germ line after gene targeting. Wild-type thymocytes readily undergo apoptosis after treatment with ionizing radiation, the glucocorticoid methylprednisolone, or etoposide (an inhibitor of topoisomerase II), or after Ca(2+)-dependent activation by phorbol ester and a calcium ionophore. In contrast, homozygous null p53 thymocytes are resistant to induction of apoptosis by radiation or etoposide, but retain normal sensitivity to glucocorticoid and calcium. The time-dependent apoptosis that occurs in untreated cultures is unaffected by p53 status. Cells heterozygous for p53 deletion are partially resistant to radiation and etoposide. Our results show that p53 exerts a significant and dose-dependent effect in the initiation of apoptosis, but only when it is induced by agents that cause DNA-strand breakage. |
| Databáze: | OpenAIRE |
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