The X-linked hypoxanthine-guanine phosphoribosyltransferase (hprt) gene is a target of analyses of in vivo mutation frequencies in circulating T-lymphocytes. We established a novel, accessory cell-free cloning method of T lymphocytes with a hprt mutation by a combined use of recombinant interleukin-2, conditioned medium from activating T-lymphocytes and culture plates coated with anti-CD3 monoclonal antibody. Using the method, we examined mutation frequencies of the hprt gene in T-lymphocytes from six healthy individuals, nine patients with colon cancer including two patients from different families with hereditary nonpolyposis colon cancer and six cancer-free relatives of the patients. In six healthy individuals, the mean cloning efficiency and mutation frequency (MF) of the hprt gene in T-lymphocytes were 0.51 ± 0.28 and 9.4 ± 7.5 x 10-6 respectively. These data were similar to the reported values. The mean MFs in the nine colon cancer patients (10.6 ± 7.3 x 10-6) were not significantly different from those of the 12 cancer-free individuals (11.6 ± 9.4 x 10-6). The correlation between mutation frequencies and age of the individuals was significant regardless of the presence or absence of cancers. The single-strand conformation polymorphism analyses of nested RT-PCR products of hprt mRNA were done in 33 mutant clones from five members of a family of which MF values were high. All the analyzed mutant clones show a genetic aberration in the coding region of the hprt gene. At least 28 of 33 mutants were independent. Our method provides a new versatile tool for in vivo analysis for mutations of the hprt gene.
|ジャーナル||Environmental and Molecular Mutagenesis|
|出版ステータス||Published - 1997 8 29|
ASJC Scopus subject areas
- Health, Toxicology and Mutagenesis