酵母TEL1基因对辐射诱发A-T细胞染色体畸变的影响

Effect of yeast TEL1 gene expression in A-T cells on chromosome aberration induced by radiation

目的 研究酵母TEL1基因在毛细血管扩张 运动共济失调症 (ataxia telangiectasia ,A T)A T细胞中的异位表达对辐射诱发A T细胞染色体畸变的影响。方法 稳定转染酵母TEL1全基因序列、酵母TEL1基因片断和pRep5空载体的AT TEL1、AT deltaTEL1、AT rep、GM rep细胞分别在含10 0 μg ml潮霉素的DMEM培养液中培养 ;A T细胞和正常对照的GM6 39细胞分别在DMEM培养液中常规培养。应用6 0 Co源对处于指数生长期的上述细胞进行γ射线照射 ,吸收剂量分别为 0 ,1和 3Gy。应用常规染色体技术制片 ,并进行染色体畸变分析。结果 传代培养的AT TEL1、AT del taTEL1、AT rep、A T、GM6 39、GM rep细胞的染色体数目均是非整倍体 ;无论是A T细胞染色体自发畸变率还是辐射诱发的染色体畸变率均明显高于正常对照的GM6 39纤维母细胞 ;A T细胞的高染色体畸变率主要是由于染色体双着丝粒体和染色体断片所至的染色体型畸变 ;稳定转染酵母TEL1全基因序列的AT TEL1细胞染色体自发畸变率与A T细胞之间差异无显著性 (P >0 0 5 ) ;辐射诱发AT TEL1细胞的染色体畸变率明显低于A T细胞 (P <0 0 1) ;辐射诱发AT deltaTEL1、AT rep细胞染色体畸变率则高于A T细胞。结论 酵母TEL1基因在A T细胞中的异位表达 ,能够明显降低电离辐射诱发?

Objective To analyze the effect of yeast TEL1 gene expression in human A\|T (ataxia\|telangiectasia) cells on chromosome aberration induced by radiation. Methods\ Yeast TEL1 gene (TEL1rep),TEL1 fragment (deltaTELrep),pRep5 vector were stably transfected into A\|T cells and pRep5 vector was stably transfected into GM639 cells.respectively.The stably transfected A\|T and GM639 cells,namely,AT\|TEL1,AT\|deltaTEL1,AT\|rep,GM\|rep,were grown selectively in Dulbecco's minimal essential medium (DMEM) containing 100 μg/ml hygromycin,while non\|transfected A\|T and GM639 cells were grown in DMEM containing 15%\|20% FBS. 60 Co γ\|rays were used to irradiate the above cells at exponential phase.The irradiation dose was 0,1,3 Gy,respectively.A hundred metaphases were analyzed for microscopically detectable chromosome type and chromatid type aberrations. Results\ The chromosome numbers of all transfected,and non\|transfected A\|T,GM639 fobroblasts were aneuploid.Both spontaneous and radiation\|induced chromosome aberration frequencies of A\|T cells were higher than those of GM639 control cells.There is no significant difference in the spontaneous chromosome aberration between TEL1 gene stably transfected A\|T cells (AT\|TEL1) and non\|transfected A\|T cells ( P >0 05).Chromosome aberration frequencies induced by radiation in AT\|TEL1 cells were significantly lower than those of A\|T cells ( P <0 01).However,chromosome aberration frequencies induced by radiation in AT\|deltaTEL1 and AT\|rep cells were higher than those of A\|T cells. Conclusion\ The expression of yeast TEL1 gene in human A\|T cells can significantly decrease the chromosome aberration frequencies induced by radiation.