摘要
DNA methylation is a critical epigenetic mechanism that influences gene transcription, genomic stability, X-chromosome inactivation and other factors, and appropriate DNA methylation is crucial in development. DNA methyltransferase 1 （DNMT1） plays an important role in maintaining the established methylation pattern during DNA replication. Although the effect of DNA methylation on embryonic development has been well known in vertebrates, little research has been carried out in invertebrates, especially in marine bivalves. In this study, the DNMT1 gene （MyDNMT1） was firstly identified from Mizuhopecten yessoensis. The full-length cDNA of MyDNMT1 was 5 039 bp, consisted of a 5＇ untranslated region （5＇-UTR） of 79 bp, a 3＇ untranslated region （3＇-UTR） of 199 bp, and a 4 761 bp open reading frame （ORF） encoding a peptide of 1 586 amino acids without a putative signal peptide. The relative mRNA expression level of MyDNMT1 was measured during the embryonic development of M. ydssoensis using real-time PCR, which revealed that the level at stage zygote and trochophore were significantly higher than that at other stages. We further examined the global DNA methylation during development by colorimetric method. The results showed that the methylation level was increased and reached the peak at blastula stage, then dramatically decreased, and fluctuated at early D-shaped larva stage. This study provided greater insight into the DNA methylation of embryonic development, which obtained a better understanding of the relationship between the DNA methylation and the embryonic development in bivalve mollusks.
该研究通过基因克隆的方法获得了虾夷扇贝DNMT1基因(MyDNMT1)的cDNA,全长5 039 bp,其中包括开放阅读框4 761bp,编码1 586个氨基酸,其5’端非编码区为79 bp,3’端非编码区为199 bp。基因相对表达量分析结果显示,MyDNMT1表达起初呈下降趋势,发育至担轮幼虫时期骤然升高,之后再次降低。发育不同时期整体甲基化水平测定结果显示,全基因组甲基化水平最初呈上升趋势,至囊胚期达到最高,随后降低至担轮幼虫时期后再次升高,发育至早期面盘幼虫时期整体甲基化水平再次下降。结合基因相对表达量分析,全基因组甲基化水平动态变化可能是MyDNMT1基因表达与其酶反应之间存在延迟的表现,且推测发育至担轮幼虫后,全基因组甲基化水平的变化与发育过程中出现细胞分化有关。
基金
Supported by Earmarked Fund for Modern Agro-industry Technology Research System of China(CARS-49)
Natural Science Foundation of Liaoning Province(201602408)~~
