One of the prices we pay for living in an industrial and technological society is exposure to a variety of chemical and radiation mutagens. Examples of this exposure are contaminating levels of Cs-137 remaining from the Chernobyl disaster and increased exposure to UV due to thinning of the ozone layer. Both events are expected to result in increased numbers of cancers. Although it is possible to readily detect this exposure if it occurs at high dose, it is far more difficult to detect this exposure if it occurs at low dose or if the possibility of exposure is raised after it has occurred. One potential means of addressing this problem is to determine the spectrum of mutations induced by a specific mutagen and then determine if this spectrum is present in genomic DNA in cells taken from individuals at risk. This grant proposal involves using a cultured mouse stem cell system to determine more accurately the spectrum of mutation induced by ionizing radiation. The first specific aim is to determine the mutational spectrum induced by high dose high and low LET ionizing radiation and compare and contrast this spectrum with those spectra produced by equally genotoxic doses of UV and an alkylating chemical mutagen, as well as with the spontaneous spectrum. Having defined the ionizing radiation spectrum, the second specific aim is to determine the lowest possible dose at which all or part of this spectrum can be recognized. The third and final specific aim is to determine if the ionizing radiation induced mutational spectrum is altered in morphologically differentiated cells derived from the stem cells. Such a comparison has not been performed previously. The mouse cell lines to be used are unique because they have heterozygous deficiencies for the purine salvage gene aprt (adenine phosphoribosyltransferase) and because they contain two chromosome 8 homologs, which harbor the aprt gene, that are distinguishable with a molecular analysis. Cells with homozygous deficiencies, which will be induced with the above mutagens, will be selected and a molecular analysis used to elucidate and enumerate the spectrum of mutations. This molecular analysis will include Southern blots, PCR, and DNA sequencing.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA056383-02
Application #
3200768
Study Section
Special Emphasis Panel (SRC (40))
Project Start
1992-04-01
Project End
1996-03-31
Budget Start
1993-04-01
Budget End
1994-03-31
Support Year
2
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Kentucky
Department
Type
Schools of Medicine
DUNS #
832127323
City
Lexington
State
KY
Country
United States
Zip Code
40506
Connolly, Lanelle; Lasarev, Michael; Jordan, Robert et al. (2006) Atm haploinsufficiency does not affect ionizing radiation mutagenesis in solid mouse tissues. Radiat Res 166:39-46
Wang, Qi; Ponomareva, Olga N; Lasarev, Michael et al. (2006) High frequency induction of mitotic recombination by ionizing radiation in Mlh1 null mouse cells. Mutat Res 594:189-98
Shin-Darlak, Chi Y; Skinner, Amy M; Turker, Mitchell S (2005) A role for Pms2 in the prevention of tandem CC --> TT substitutions induced by ultraviolet radiation and oxidative stress. DNA Repair (Amst) 4:51-7
Turker, Mitchell S; Schwartz, Jeffrey L; Jordan, Robert et al. (2004) Persistence of chromatid aberrations in the cells of solid mouse tissues exposed to 137Cs gamma radiation. Radiat Res 162:357-64
Breger, Kevin S; Smith, Leslie; Turker, Mitchell S et al. (2004) Ionizing radiation induces frequent translocations with delayed replication and condensation. Cancer Res 64:8231-8
Turker, Mitchell S (2003) Autosomal mutation in somatic cells of the mouse. Mutagenesis 18:1-6
Shin, Chi Y; Ponomareva, Olga N; Connolly, Lanelle et al. (2002) A mouse kidney cell line with a G:C --> C:G transversion mutator phenotype. Mutat Res 503:69-76
Shin, Chi Y; Turker, Mitchell S (2002) A:T --> G:C base pair substitutions occur at a higher rate than other substitution events in Pms2 deficient mouse cells. DNA Repair (Amst) 1:995-1001
Ponomareva, Olga N; Rose, Jennifer A; Lasarev, Michael et al. (2002) Tissue-specific deletion and discontinuous loss of heterozygosity are signatures for the mutagenic effects of ionizing radiation in solid tissues. Cancer Res 62:1518-23
Shin, Chi Y; Mellon, Isabel; Turker, Mitchell S (2002) Multiple mutations are common at mouse Aprt in genotoxin-exposed mismatch repair deficient cells. Oncogene 21:1768-76

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