~(60)Coγ射线照射对人脆性组胺酸基因表达的影响

目的:研究人脆性组胺酸三联体(fragile histidine triad,FHIT)基因在电离辐射损伤过程中的动态变化.方法:以SV40病毒转染的永生化人支气管上皮细胞株BEAS-2B细胞为照射对象,分为0.5、1、2、4、8、16 Gy 60Co γ射线照射剂量组和未照射对照组,分别于照射后24 h、72 h和10 d,采用单细胞RT-PCR技术以及PCR产物直接测序法检测FHIT基因的表达情况.结果:对照组各时间点均未检出异常FHIT转录本,不同剂量照射组照射后各时间点均不同程度检出异常缺失FHIT转录本,照射后24 h各组突变百分比分别为52.6%、66.7%、57.9%、76.5%、64.7%和81.3%,照射后72 h各组突变百分比分别为17.6%、22.2%、50.0%、47.4%、47.1%和68.4%,照射后10 d各组突变百分比分别为21.1%、25.0%、60.0%、57.9%、61.1%和68.4%;突变体经测序证实为外显子缺失性突变.结论:电离辐射可引起FHIT基因的缺失突变.

Change of human fragile histidine triad gene expression in BEAS-2B cells irradiated with 60Co γ-ray

Objective:To study dynamic changes of fragile histidine triad(FHIT) gene expression in ionizing radiation injury and radiation carcinogenesis. Methods: BEAS-2B cells were divided into 0.5,1,2,4,8,16 Gy irradiation groups and control group. In 24 h, 72 h and 10 d after irradiation, the expression of FHIT gene was studied with single-cell RT-PCR and DNA sequencing separately. Results: Different types of FHIT gene mutations occured in different phases after irradiation with different doses (All mutations were exon deletion mutations by DNA sequencing), while abnormal FHIT gene was not detected in control group. The percentage of mutation in 0.5,1,2,4,8,16 Gy dose groups was 52.6%,66.7%,57.9%,76.5%,64.7% and 81.3% respectively 24 h after irradiation;17.6%,22.2%,50.0%,47.4%,47.1% and 68.4% respectively 72 h after irradiation;and 21.1%,25.0%,60.0%,57.9%,61.1% and 68.4% respectively 10 d after irradiation. Conclusion: These results suggest that ionizing radiation can cause deletion of FHIT gene.