Complex hprt deletion events are recovered after exposure of human lymphoblastoid cells to high-LET carbon and neon ion beams.
Hypoxanthine phosphoribosyltransferase gene (hprt) mutations were induced in human TK-6 lymphoblastoid cells by irradiation at a linear energy transfer (LET) of 250 or 310 keV/micron for carbon and neon ions, respectively. At such a high level of LET, ions will lose most of their total energy and stop shortly after passing through the cell. The hprt mutations were analyzed by multiplex PCR, long-PCR and DNA sequencing of both genomic and cDNA. Over half of the C ion-induced hprt mutations (10 of 19) were point mutations, in contrast to 15% of the mutations induced by Ne ions (three of 20). The remaining 47 and 85% of the C and Ne ion-induced mutants, respectively, are deletion events. The latter events include three complex losses of multiple non-contiguous exon regions in both ion irradiation collections. We note that mutations involving the exon 6 region are frequent in the Ne ion collection: all three of the complex events retained the exon 6 region with flanking deletion of sequence and three other mutants involved deletion of this region. It may be concluded that these high-LET C and Ne ion irradiations produce different mutational spectra.
Kagawa
Y
Y
Division of Radioisotope Technology, Institute of Physical and Chemical Research, Saitama, Japan.
Shimazu
T
T
Gordon
A J
AJ
Fukunishi
N
N
Inabe
N
N
Suzuki
M
M
Hirano
M
M
Kato
T
T
Watanabe
M
M
Hanaoka
F
F
Yatagai
F
F
D002244:Carbon / Q000633:toxicity; D017357:Cyclotrons; D017931:DNA Primers; D004307:Dose-Response Relationship, Radiation; D020450:Heavy Ions / Q000009:adverse effects*; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D007938:Leukemia / Q000378:metabolism*; D018499:Linear Energy Transfer; D008957:Models, Genetic; D016296:Mutagenesis; D009356:Neon / Q000633:toxicity; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D009356:Neon; D002244:Carbon; D007041:Hypoxanthine Phosphoribosyltransferase