DNA Methylation Variation Trends during the Embryonic Development of Chicken.
DNA Methylation Variation Trends during the Embryonic Development of Chicken.
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DOI：
10.1371/journal.pone.0159230
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Yang X
中科院分区：
文献类型：
--
作者：
Li S;Zhu Y;Zhi L;Han X;Shen J;Liu Y;Yao J;Yang X
胚胎发生期是表观遗传重编程的关键时期，因此在家禽表观遗传学研究领域中对于阐明鸟类胚胎发育期间DNA甲基化变化的趋势，特别是由于鸟类和哺乳动物之间胚胎发生的差异，具有重要意义。本研究首先以肉鸡为模式生物，通过高效液相色谱法检测了鸡胚胎发生过程中基因组DNA甲基化的变化。然后，我们使用亚硫酸氢盐测序聚合酶链反应方法鉴定了两个特定基因（IGF 2和TNF-α）的启动子和基因体的DNA甲基化程度。此外，我们还检测了IGF 2、TNF-α和DNA甲基转移酶（DNMT）1、3a和3b的表达水平。我们的研究结果表明，在胚胎发育过程中，肝脏，心脏和肌肉的基因组DNA甲基化水平增加，肝脏的甲基化水平在中期后期显着较高。在肌肉和肝脏中，TNF-α的启动子甲基化水平先升高后降低，而基因体甲基化水平在E8、11和14胚龄时保持较低，然后在E17时显着升高。IGF 2基因启动子区甲基化水平持续下降，而基因体甲基化水平持续升高。TNF-α的表达在E8、E11和E14之间没有发现差异，而在E17观察到显著增加。IGF 2在胚胎发育过程中表达水平逐渐升高。此外，DNMTs的mRNA和蛋白水平随着胚胎年龄的增加而增加。这些结果表明，鸡在胚胎期表现出增加的基因组DNA甲基化模式。此外，组织中基因组DNA甲基化水平与基因表达水平密切相关，基因表达可能同时受到启动子低甲基化和基因体高甲基化的调控。
The embryogenesis period is critical for epigenetic reprogramming and is thus of great significance in the research field of poultry epigenetics for elucidation of the trends in DNA methylation variations during the embryonic development of birds, particularly due to differences in embryogenesis between birds and mammals. Here, we first examined the variations in genomic DNA methylation during chicken embryogenesis through high-performance liquid chromatography using broilers as the model organism. We then identified the degree of DNA methylation of the promoters and gene bodies involved in two specific genes (IGF2 and TNF-α) using the bisulfite sequencing polymerase chain reaction method. In addition, we measured the expression levels of IGF2, TNF-α and DNA methyltransferase (DNMT) 1, 3a and 3b. Our results showed that the genomic DNA methylation levels in the liver, heart and muscle increased during embryonic development and that the methylation level of the liver was significantly higher in mid-anaphase. In both the muscle and liver, the promoter methylation levels of TNF-α first increased and then decreased, whereas the gene body methylation levels remained lower at embryonic ages E8, 11 and 14 before increasing notably at E17. The promoter methylation level of IGF2 decreased persistently, whereas the methylation levels in the gene body showed a continuous increase. No differences in the expression of TNF-α were found among E8, 11 and 14, whereas a significant increase was observed at E17. IGF2 showed increasing expression level during the examined embryonic stages. In addition, the mRNA and protein levels of DNMTs increased with increasing embryonic ages. These results suggest that chicken shows increasing genomic DNA methylation patterns during the embryonic period. Furthermore, the genomic DNA methylation levels in tissues are closely related to the genes expression levels, and gene expression may be simultaneously regulated by promoter hypomethylation and gene body hypermethylation.