Intrachromosomal telomere-related sequences and gpt locus sensitivity to ionizing radiation
- Argonne National Laboratory, IL (United States)
The Chinese hamster ovary cell line CHO-T510 contains a single copy of a stably integrated retroviral vector with a selectable marker, the E. coli xanthine-guanine phosphoribosyl transferase (gpt) gene. Previous studies on the CHO-T510 line showed that, in comparison with other genetic loci, the gpt locus was hypersensitive to mutation induction by ionizing radiation. Southern blot analyses of a set of 20-26 gpt{sup -} mutant lines, isolated as either spontaneous, gamma-induced, or alpha-radiation-induced mutants, indicated that 86-95% of these were complete vector deletions. The integrated gpt vector was localized by in situ hybridization to the q arm of chromosome 5 in close proximity to the interstitial ttelomeresequences near the pericentric region of this chromosome. One to three kilobases of sequences adjacent to the gpt integration site were clones and analyzed. Both the right and left integration sites contain sequences that hybridize to a pantelomere probe, suggesting that the vector has acquired telomeric repeats at its ends. The radio-sensitivity of the gpt locus may be due to these telomere repeats, as interstitial telomeres have been reported to be radiation-sensitive fragile sites. The gpt locus in the T510 line affords a unique resource to test this hypothesis.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 88906
- Report Number(s):
- CONF-9405324-; ISSN 0893-6692; TRN: 95:017973
- Journal Information:
- Environmental and Molecular Mutagenesis, Vol. 23, Issue Suppl.23; Conference: 25. annual meeting of the Environmental Mutagen Society, Portland, OR (United States), 7-12 May 1994; Other Information: PBD: 1994
- Country of Publication:
- United States
- Language:
- English
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