低温压力下水通道蛋白1b(aqp1b)基因的表达及表观调控

Expression and Epigenetic Regulation of 1b(aqp1b) Gene in Aquaporin Under Cold Stress

水通道蛋白是(aquaporins,AQPs)介导水分子被动跨膜转运的内在膜蛋白。本研究发现在低温胁迫下斑马鱼胚胎成纤维细胞(ZF4)中aqp1b基因相对表达水平显著升高,为研究低温胁迫下斑马鱼水通道蛋白(aqp1b)基因的表达调控机制,采用染色质免疫共沉淀-实时荧光定量PCR(Ch IP-q PCR)法和甲基化DNA免疫沉淀-实时荧光定量PCR(Me DIP-q PCR)法,研究低温压力下ZF4细胞中aqp1b基因启动子区域组蛋白修饰和DNA甲基化水平的变化。Ch IP-q PCR分析表明:低温处理5 d后aqp1b基因启动子区域H3K4me3(激活性组蛋白修饰标志)修饰水平比对照组显著提高3.1倍(p<0.05);而H3K27me3(抑制性组蛋白修饰标志)修饰水平比对照组显著降低2.1倍(p<0.01)。Me DIP-q PCR分析表明:低温处理组aqp1b基因启动子区域甲基化水平比对照组显著下调7.3倍(p<0.01)。研究表明,低温压力下ZF4细胞中aqp1b基因的表达受到了表观遗传机制调控以适应低温压力。

Aquaporins （AQPs） arc integral membrane proteins which facilitate passive permeation of water molecules across membranes. Our study found that aqp lb gene expression level in zebrafish embryonic fibroblast cells （ZF4） significantly increased under cold stress. To investigate the regulatory mechanism of aqp 1b in AQPs of zebrafish under cold stress, chromatin immunoprecipitation-quantitative real time PCR （ChIP-qPCR） and methylated DNA immunoprecipitation-quantitative Real-time PCR （MeDIP-qPCR） were used to detect histone modifications and DNA methylation at the promoter region of aqp 1b gene in ZF4 cells under cold stress. ChIP-qPCR data indicated that the the modification level of H3K4me3 at the promoter region of aqp 1b gene significantly increased by 3.1 times under cold stress for 5 days compared with that of the control group （p〈0.05）. however, the modification level of H3K27me3 decreased by 2.1 times compared with that of the control group （p〈0.01）. The results of MeDIP-qPCR indicated that DNA methylation level at the promoter region ofaqp1b significantly decreased by 7.3 times under cold stress compared with that of the control group （p〈0.01）. Our study suggested that the expression of aqp lb gene in ZF4 cells under cold stress was regulated by epigenetic mechanism to response to cold stress.