重金属镉胁迫对果蝇dDnmt2、dMBD2/3表达量的影响
The effects of cadmium on expression of the dDnmt2 anddMBD2/3 genes in Drosophila melanogaster
管德龙 梁 露 张 敏
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作者单位：陕西师范大学 生命科学学院，西安 710062
中文关键词：镉，黑腹果蝇，DNA甲基化修饰系统基因，可遗传性
英文关键词： cadmium, Drosophila melanogaster, DNA methylation system genes, hereditability
中文摘要：
【目的】 探明重金属镉（Cadmium, Cd）对黑腹果蝇Drosophila melanogaster DNA甲基化修饰相关基因表达的影响，初步分析镉胁迫可能导致果蝇的表观遗传变异及其可遗传性。【方法】 收集8 h内羽化未交配的雌、雄果蝇，在添加不同质量浓度（0、0.9375、1.875、3.75、7.5、15.0、30.0、60.0 mg/kg）Cd的培养基中培养，以Real-time PCR定量检测亲代（F0）果蝇生殖系统、去生殖系统体细胞、整体表达量变化趋势及解除胁迫的子代（F1）果蝇DNA甲基化修饰系统相关基因（dDnmt2、dMBD2/3）在mRNA水平的表达变化。【结果】 重金属镉胁迫诱导了果蝇卵巢、精巢、去卵巢雌果蝇、去精巢雄果蝇、完整雌果蝇、完整雄果蝇的dDnmt2、dMBD2/3在mRNA水平的表达上调，呈现一定剂量依赖性及雌、雄组织差异性，且这种表达变化持续至子一代。【结论】 研究结果揭示了重金属镉胁迫可诱导果蝇dDnmt2、dMBD2/3表达量上调，其可能与果蝇的DNA甲基化修饰过程相关联，导致表观遗传变异并可能向子代传递。
英文摘要： [Objectives] To investigate the effects of heavy metal cadmium (Cd) on the expression of DNA methylation-related genes, and discuss potential epigenetic variation caused by cadmium stress and its heritability in Drosophila melanogaster. [Methods] Unmated male and female flies < 8 h old were collected and incubated in culture medium containing different concentrations of Cd (0.0, 0.9375, 1.875, 3.75, 7.5, 15.0, 30.0, 60.0 mg/kg) for 10 days. Quantitative Real-time PCR was used to detect the mRNA expression of the DNA methylation-related genes, dDnmt2 and dMBD2/3 in the reproductive system of parental (F0) flies with Cd treatment and their offspring (F1) without Cd. [Results] Cadmium stress can up-regulate the expresion of dDnmt2 and dMBD2/3 in the ovaries and testes and these changes continue to the next generation (F1). [Conclusion] Expression of dDnmt2 and dMBD2/3 in D. melanogaster is positively correlated with cadmium exposure. This may due to the DNA methylation modification process associated with epigenetic variation in D. melanogaster.