拟南芥根端干细胞DNA甲基化的动态变化及其对γ-氨基丁酸响应的模式研究

Dynamic Changes of DNA Methylcytosine in Arabidopsis Root Stem Cells and Their Responses to γ-aminobutyric Acid

为探讨γ-氨基丁酸(γ-aminobutyric acid,GABA)对DNA胞嘧啶(C)甲基化(5m C)可能的调节机制,该研究以拟南芥的根和愈伤组织为研究材料,分析了经γ-氨基丁酸处理后,5m C的含量及其对GABA信号的响应规律。结果表明,GABA处理显著降低了拟南芥根中DNA 5m C的含量,增加了5-羟甲基胞嘧啶(5hm C)含量;但GABA处理增加了根愈伤组织中5m C含量,降低了5m C的去甲基化过程。这一现象在愈伤组织来源的静止中心细胞(p WOX5-GFP特异性标记)及其周围的干细胞(surrounding stem cells)的继代培养的愈伤组织中得到了进一步验证。研究结果证实了外源性GABA信号触发的DNA甲基化的动态变化在拟南芥的根及其愈伤组织的生长中对GABA的响应具有不同的调节模式,这种模式可能与GABA对干细胞的分裂和干细胞命运的维持有关。

In order to study γ-aminobutyric acid（GABA） on cytosine methylation（5m C） in genomic DNA and its possible regulatory mechanisms, we use Arabidopsis roots and root calluses as the research materials to analyze 5m C content and its responding mechanism to GABA signal. The results showed that GABA（1.0 mmol/L） treatment significantly decreased 5m C content in Arabidopsis root, and concurrently increased 5-hydroxymethyl cytosine（5hm C） content. In contrast, GABA had increased the content of 5m C in the calluses arising from roots, and reduced the product of 5m C demethylation（via 5hm C）. This phenomenon was also observed and validated in the subculture of callus deriving from quiescent centre cells（p WOX5-GFP marker） and their surrounding stem cells. Our results demonstrated time that the dynamic changes of DNA methylation triggered by exogenous GABA signal had different patterns in Arabidopsis growing roots and their calluses. These different patterns are possibly linked with cell division and the maintenance of stem cell fate.