作 者：
胡浪;郭青青;刘烨蓉;胡章立;王江新;雷安平
单 位：
深圳大学 生命与海洋科学学院/深圳市海洋生物资源与生态环境重点实验室/深圳市海洋藻类生物开发与应用工程实验室/广东省植物表观遗传学重点实验室
关键词：
固氮蓝藻;异形胞;缺氮胁迫;DNA甲基化;鱼腥藻
摘 要：
为研究缺氮胁迫对固氮蓝藻DNA甲基化的影响,本研究以固氮蓝藻鱼腥藻Anabaena sp.PCC 7120为试验材料,比较了正常藻丝、缺氮藻丝和异形胞的DNA甲基化修饰.DNA甲基化修饰与细胞分化、基因组印记等多种重要生物学过程有关.在高等植物和非固氮蓝藻中,缺氮胁迫可以改变DNA甲基化修饰模式.DNA甲基化修饰也存在于固氮蓝藻细胞中.然而,固氮蓝藻可以通过固定空气中的氮来缓解缺氮压力,缺氮胁迫是否能改变固氮蓝藻的DNA甲基化修饰模式尚不清楚.全基因组重亚硫酸盐测序可以在单碱基水平分析基因组范围内所有胞嘧啶的甲基化修饰模式.利用全基因组重亚硫酸盐测序对正常培养的藻丝、 缺氮72h的藻丝和异形胞的胞嘧啶甲基化进行了测序,分别获得6.25,8.38,7.11Gb的干净数据.在正常培养的藻丝、缺氮72h的藻丝和异形胞中,甲基化胞嘧啶位点占所有胞嘧啶位点的比例分别为1.06%,1.05%和1.05%,甲基化胞嘧啶位点的平均甲基化水平分别为0.61%,0.54%和0.54%.基于胞嘧啶甲基化修饰模式对这3个样品进行Pearson相关性分析,发现样品间的相关系数在0.976~0.983之间.这些结果说明正常培养的藻丝、缺氮72h的藻丝和异形胞的DNA甲基化修饰模式相似,缺氮胁迫不能引起固氮蓝藻DNA甲基化模式的改变.本结果为固氮蓝藻和非固氮蓝藻采用不同的表观修饰来应对缺氮胁迫提供了证据.
译 名：
Effects of Nitrogen Deficiency Stress on DNA Methylation Patterns in the Nitrogen-fixing Cyanobacterium, Anabaena sp. PCC7120
作 者：
HU Lang;GUO Qing-qing;LIU Ye-rong;HU Zhang-li;WANG Jiang-xin;LEI An-ping;College of Life Sciences and Oceanography/Shenzhen Key Laboratory of Marine Bioresource&Eco-environmental Science/Shenzhen Engineering Laboratory for Marine Algal Biotechnology/Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen University;College of Materials Science and Engineering/Nanshan District Key Lab for Biopolymers and Safety Evaluation, Shenzhen University;
关键词：
nitrogen-fixing cyanobacteria;;heterocyst;;nitrogen deficiency stress;;DNA methylation;;Anabaena
摘 要：
In order to study the effect of nitrogen deficiency stress on DNA methylation of nitrogen-fixing cyanobacteria,Anabaena sp. PCC7120 was investigated to compare DNA methylation patterns of filaments under both normal and nitrogen deficiency conditions and heterocysts in this study. DNA methylation is associated with many important biological processes such as cell differentiation and genomic imprinting. In higher plants and non-nitrogen-fixing cyanobacterium, nitrogen deficiency can modify their DNA methylation patterns. DNA methylation also exists in nitrogen-fixing cyanobacteria, However, there are nitrogen-fixing cyanobacteria which can fix nitrogen to alleviate the deficiency. Whether nitrogen deficiency can modify the DNA methylation remains unknown in nitrogen-fixing cyanobacteria. Whole genome bisulfite sequencing can be used to analyze all cytosine methylation patterns across the genome at a single base level. In this study, the cytosine methylations of filaments under normal condition and after 72 hours of nitrogen deficiency and that of heterocysts were studied using whole genome bisulfite sequencing, and 6.25,8.38,7.11 Gb clean data were obtained respectively. The sites for cytosine methylation account for 1.06%,1.05% and 1.05% of all the cytosine sites in the filament under normal nitrogen condition, filament under nitrogen deficiency and heterocyst, respectively. The mean methylation levels of the sites for cytosine methylation in filament under normal nitrogen condition, filament under nitrogen deficiency and heterocyst are 0.61%, 0.54%, and 0.54%, respectively. Pearson correlation analysis based on cytosine methylation modification showed that the correlation coefficients among the samples were between0.976 and 0.983. These results indicate that DNA methylations in the three samples were similar and nitrogen deficiency stress cannot modify DNA methylation in nitrogen-fixing cyanobacteria. This study provides evidences for nitrogen-fixing cyanobacteria and non-solitary cyanobacteria to deal with nitrogen deficiency stress by using different epigenetic modifications
