@misc{oai:repo.qst.go.jp:00068243,
 author = {Amasaki, Yoshiko and Kakinuma, Shizuko and Yamauchi, Kazumi and Nishimura, Mayumi and Imaoka, Tatsuhiko and Shimada, Yoshiya and 甘崎 佳子 and 柿沼 志津子 and 山内 一己 and 西村 まゆみ and 今岡 達彦 and 島田 義也},
 month = {Nov},
 note = {Ikaros is a potent tumor suppressor gene in both human and murine leukemogenesis.  We previously showed Ikaros alteration type is differed between X-ray-induced murine thymic lymphoma (TL) and N-ethyl-N-nitrosourea (ENU) -induced TL. Thus, X-ray-induced TL was characterized by altered splicing, null expression and point mutations, which were accompanied by by loss of heterozygosity (LOH). ENU-induced TL harbored only point mutation without LOH. We showed that combined treatment of X-rays (0.8-1.0 Gy x 4 times) and ENU (100, 200ppm) synergistically increased TL incidence. The aim of the curresnt study is to elucidate the underlying mechanism in the lymphomagenesis induced by combined treatment of X-rays and ENU. In this study, we analyzed the mutation status of Ikaros in the TLs induced by combined (X-rays following ENU) treatment.  
B6C3F1 mice (4-week-old female) were irradiated by X-rays (0.2 - 1.0 Gy a week x 4 times) and then treated by EMU (50 - 200 ppm in drinking water) from 8-week-old. The analyses of LOH on chromosome 11, expression by RT-PCR and western blotting, and mutation by sequence were performed. 
Ikaros splicing and null expression was observed in X-ray-induced TL was 10 and12%, ENU-induced TL was both 0%, combined-induced TL was 6 and 0%. Point mutation and LOH status were 26%(LOH:73%) in X-ray-induced TL 26%(LOH:0%) in ENU-induced TL. In combined-induced TL, that was increased to 40% (LOH: 20%), it is ENU type. Thus, X-rays plays a promoter for ENU-induced leukemogenesis in the TL induced by X-rays following ENU., 第48回日本放射線影響学会／第1回アジア放射線研究会議},
 title = {Combined effects of X-rays and N-ethyl-N-nitrosourea in murine thymic lymphoma s -(2) Analysis in Ikaros point mutation-},
 year = {2005}
}