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Low doses of neutrons induce changes in gene expression

Journal Article · · Radiation Research
DOI:https://doi.org/10.2307/3578762· OSTI ID:56767
;  [1]; ;  [2]
  1. Argonne National Lab., IL (United States)
  2. Loyola Univ. of Chicago, Maywood, IL (United States)
Studies were designed to identify genes induced in fibroblasts after exposure to low-dose neutron radiation but not after {gamma} rays. Our past work had shown similar modulation of transcripts for {alpha}-tubulin, {beta}- and {gamma}-actins, ornithine decarboxylase and interleukin 1 after exposure to either neutrons or {gamma} rays. However, differences in the expression of {beta}-protein kinase C and c-fos genes were observed, with both being induced after exposure to {gamma} rays but not neutrons. Recently, we have identified two genes that are induced after exposure to neutrons but not {gamma} rays: Rp-8 (a gene associated with apoptosis) and the long terminal repeat (LTR) of the human immunodeficiency virus (HIV). Induction of Rp-8 mRNA was demonstrated in Syrian hamster embryo (SHE) fibroblasts and was found to be induced in cells exposed to neutrons administered at low (0.005 Gy/min) and high dose rate (0.12 Gy/min). No induction of other genes associated with apoptosis such as Rp-2, bcl-2 and Tcl-30 was observed. The induction of transcription from the LTR of HIV was demonstrated in HeLa cells bearing a transfected construct of the chloramphenicol acetyl transferase (CAT) gene driven by the HIV-LTR promoter. Measurements of CAT activity and CAT transcripts after irradiation demonstrated an unresponsiveness to {gamma} rays over a broad range of doses (0.1-3 Gy). Twofold induction of the HIV-LTR was detected after exposure to neutrons (0.48 Gy) administered at low (0.05 Gy/min) but not high (0.12 Gy/min) dose rates. Ultraviolet-mediated HIV-LTR induction, however, was inhibited by exposure to low-dose-rate neutron irradiation. These results are interesting in light of reports that Rp-8 is induced during apoptosis and that HIV causes apoptosis. 17 refs., 3 figs., 1 tab.
Research Organization:
Argonne National Laboratory (ANL), Argonne, IL
DOE Contract Number:
W-31109-ENG-38
OSTI ID:
56767
Report Number(s):
CONF-9305202--
Journal Information:
Radiation Research, Journal Name: Radiation Research Journal Issue: 1 Vol. 138; ISSN 0033-7587; ISSN RAREAE
Country of Publication:
United States
Language:
English