急性温度胁迫对虾夷扇贝(Patinopecten yessoensis)基因组DNA甲基化的影响

Effects of Acute Temperature Stress on Genome-Wide DNA Methylation Profiles in Patinopecten yessoensis

为探讨急性温度胁迫对虾夷扇贝(Patinopecten yessoensis)基因组DNA甲基化水平的影响,本研究从表观遗传学角度,运用甲基化敏感扩增多态性(Methylation-sensitive amplification polymorphism,MSAP)技术比较分析了升温海水(17℃和24℃)急性胁迫虾夷扇贝(原暂养于9℃的海水中)9 h和24 h后基因组DNA甲基化的变化情况。结果显示,9对引物在各组的总扩增位点数为314–337,总甲基化位点为79–94,所占比例为23.45%–28.51%;所有处理组基因组DNA总甲基化率低于对照组,急性升温胁迫使虾夷扇贝基因组DNA发生去甲基化,而且去甲基化程度随胁迫温差增大和胁迫时间增长而增强,说明急性升温胁迫能够改变DNA甲基化水平和模式。本研究为进行虾夷扇贝抗逆基因的筛查提供了新思路和研究基础,丰富了表观遗传学在扇贝中的研究资料。

DNA methylation plays important roles in many biological processes such as gene expression regulation and genomic imprinting. Up to date, studies have mostly focused on the status of DNA methylation in different tissues of aquatic animals. Stress-inducing alteration in DNA methylation in shellfish remains elusive. Japanese scallop Patinopecten yessoensis, an economically valuable bivalve species, are only cultured in northern areas of Shandong Province and Liaoning Province in China due to their specific temperature requirement. In the present study, methylation-sensitive amplification polymorphism （MSAP） was employed to investigate the profiles of genome-wide DNA methylation of P yessoensis after acute temperature stress. P yessoensis was challenged at 17℃ and 24℃ for 9 hours and 24 hours respectively. Then DNA in the gill was extracted with traditional phenol/chloroform method. Next, each DNA sample was digested by the combination of EeoR I Hpa II, EcoR I, and Msp I, followed by the connection to adapters with T4 ligase. Nine pairs of E/HM primers were selected to study the change in genome-wide DNA methylation. Totally 314-337 amplified sites were obtained in all subjects, of which 79-94 were methylated sites, accounting for 23.45%-28.51% of all sites. The total methylation rates of all experimental groups, except for that of 24℃/24 hours, were insignificantly lower than the control level. Moreover, the reduction in methylation was positively correlated with the temperature difference and exposure time. These data implied that the level and pattern of DNA methylation could be altered by acute temperature stress. Our findings provided insight into gene screening for important traits and better understand of epigenetic dynamic in bivalves.