Cytogenetic and molecular markers of high LET radiations

Journal Article · Wed Oct 01 04:00:00 EDT 1997 · Environmental and Molecular Mutagenesis

OSTI ID:530862

Schwartz, J L ^[1]; Hsie, A W ^[2]

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1. Univ. of Washington, Seattle, WA (United States)
2. Univ. of Texas Medical Branch, Galveston, TX (United States)

High linear energy transfer (LET) radiations are more effective than low LET radiations in inducing chromosome aberrations and gene mutations in mammalian cells. The more closely spaced, clustered breaks seen with high LET radiations have been suggested to favor chromosome interchanges over chromosome interchanges. We have investigated whether analysis of the spectra of chromosome aberrations or mutations at the hypoxanthine-guanine phosphoribosytransferase (hprt) locus in Chinese hamster ovary (CHO) cells could detect a shift to more chromosome intrachanges and therefore distinguish high LET radiation exposure from low LET exposure, and whether alterations in the processing of DNA breaks would influence this process. Both the frequency and type of chromosome aberrations and hprt gene mutations were determined in CHO-K1 and xrs-5 cells exposed to {sup 60}Co gamma rays or {sup 212}Bi alpha particles. Xrs-5 is a radiosensitive derivative of CHO-K1 cells that is defective in DNA double-strand break rejoining. The ratio of dicentrics to centric rings (F-ratio) was significantly lower in alpha-exposed CHO-K1 and xrs-5 cells, consistent with a shift to more chromosome intrachanges with increasing LET. In contrast, the frequency of large interstitial deletions at the hprt locus, determined by multiplex polymerase chain reaction (PCR)-based exon deletion analysis, was essentially the same for both gamma- and alpha-exposed cells in each of the cell lines. Thus, the F-ratio can distinguish high LET from low LET radiations, and the endpoint is not influenced by differences in the processing of DNA double-strand breaks. The analysis of the spectrum of hprt mutations, however, appears unable to discriminate low LET from high LET.

• OSTI ID: 530862
• Report Number(s): CONF-9704100--; CNN: Grant 1R01CA 56434
• Journal Information: Environmental and Molecular Mutagenesis, Journal Name: Environmental and Molecular Mutagenesis Journal Issue: Suppl.28 Vol. 29; ISSN 0893-6692; ISSN EMMUEG
• Country of Publication: United States
• Language: English

Related Subjects

56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BIOLOGICAL INDICATORS
CHO CELLS
CHROMOSOMAL ABERRATIONS
GENE MUTATIONS
GENETIC EFFECTS
LET