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Author Ohnishi, T. ♦ Matsumoto, H. ♦ Xinjiang, Wang
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword BIOLOGY AND MEDICINE, APPLIED STUDIES ♦ RATS ♦ BIOLOGICAL RADIATION EFFECTS ♦ MESSENGER-RNA ♦ MAN ♦ TUMOR CELLS ♦ CELL CYCLE ♦ RADIOINDUCTION ♦ DNA REPAIR ♦ PROTEINS ♦ X RADIATION ♦ GAMMA RADIATION ♦ LOW DOSE IRRADIATION
Abstract In the study of cell-cycle events, recent attention has focused on the signal transduction pathway in which a tumor-suppressor protein, wild-type (wt) p53 protein, acts as the key protein. A major advance in recent years has been the partial elucidation of the G{sub 1}-arrest mechanism. However, the transcriptional regulation mechanisms of components of the cell-cycle machinery remain unknown. We have investigated the induction of p53, WAF1, and cdk2 after gamma-ray irradiation using two human glioblastoma cell lines, U-87MG bearing the wt p53 gene and the other, T98G, a mutant gene. After the cells have been irradiated with gamma rays at 3 Gy, the level of p53 and WAF1 mRNAs in U-87MG increased gradually for up to 10 h, whereas these mRNAs were overexpressed in T98G, and these levels remained relatively stable after irradiation. In an attempt to examine the induction of cdk2 after gamma-ray irradiation, we analyzed the level of cdk2 mRNA using the reverse transcriptase-polymerase chain reaction (RT-PCR) technique. We calculated the amounts of cdk2 mRNA relative to that of b-actin mRNA in both cell lines, then plotted them against those in nonirradiated cells. After irradiation, the level of cdk2 mRNA in U-87MG gradually increased more than twofold by 10 h after gamma-ray irradiation, whereas the level of the mRNA in T98G remained relatively stable after irradiation. This result demonstrates that wtp53 induces the expression of not only WAF1 but also cdk2. The induction of wt p53 protein accumulation in rats exposed to x radiation is also discussed.
ISSN 0003018X
Educational Use Research
Learning Resource Type Article
Publisher Date 1995-12-31
Publisher Place United States
Journal Transactions of the American Nuclear Society
Volume Number 73
Technical Publication No. CONF-951006-


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