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Free Radicals Generated by Ionizing Radiation Signal Nuclear Translocation of p53The p53 tumor suppressor is a transcription factor that regulates several pathways, which function collectively to maintain the integrity of the genome. Nuclear localization is critical for wild-type function. However, the signals that regulate subcellular localization of p53 have not been identified. Here, we examine the effect of ionizing radiation on the subcellular localization of p53 in two cell lines in which p63 is normally sequestered in the cytoplasm and found that ionizing radiation caused a biphasic translocation response. p53 entered the nucleus 1-2 hours postirradiation (early response), subsequently emerged from the nucleus, and then again entered the nucleus 12-24 hours after the cells had been irradiated (delayed response). These changes in subcellular localization could be completely blocked by the free radical scavenger, WR1065. By comparison, two DNA-damaging agents that do not generate free radicals, mitomycin C and doxorubicin, caused translocation only after 12-24 h of exposure to the drugs, and this effect could not be inhibited by WR1065. Hence, although all three DNA-damaging agents induced relocalization of p53 to the nucleus, only the translocation caused by radiation was sensitive to free radical scavenging. We suggest that the free radicals generated by ionizing radiation can signal p53 translocation to the nucleus.
Document ID
20000110943
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Martinez, J. D.
(Arizona Univ. Tucson, AZ United States)
Pennington, M. E.
(Arizona Univ. Tucson, AZ United States)
Craven, M. T.
(Arizona Univ. Tucson, AZ United States)
Warters, R. L.
(Utah Univ. Salt Lake City, UT United States)
Date Acquired
August 19, 2013
Publication Date
September 1, 1997
Publication Information
Volume: 8
Subject Category
Aerospace Medicine
Funding Number(s)
CONTRACT_GRANT: DOE-307190
CONTRACT_GRANT: NIH-R29-CA-64842
CONTRACT_GRANT: NIH-R29-CA-23074
CONTRACT_GRANT: HHMI-71109-52130
CONTRACT_GRANT: NAGW-4914
Distribution Limits
Public
Copyright
Other

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