全基因组DNA甲基化揭示西方蜜蜂表观遗传印迹

Genome-wide DNA Methylation Revealing Epigenetic Inheritance Marks in Honeybee(Apis mellifera)

【目的】旨在研究全基因组甲基化在蜜蜂体内的表观遗传印迹。【方法】以西方蜜蜂(Apis mellifera)作为试验材料,对G0代蜂王进行单雄授精,待G0代蜂王产卵后,以卵(E)、1日龄工蜂幼虫(L1)、2日龄幼虫(L2)分别培育出以卵培育的G1代蜂王(G1E)、以1日龄幼虫培育的G1代蜂王(G1L1)、以2日龄幼虫培育的G1代蜂王(G1L2),选取以上3种G1代蜂王分别产卵培育G1E产的G2代雄蜂(G2DE)、G1L1产的G2代雄蜂(G2DL1)及G1L2产的G2代雄蜂(G2DL2)。利用全基因组Bisulfite甲基化测序技术,对G0代蜂王、G1代蜂王、G2代雄蜂进行全基因组DNA甲基化测序。使用one-way ANOVA分析和高甲基化位点比对揭示西方蜜蜂(A. mellifera)DNA甲基化印迹特性以及移虫日龄对西方蜜蜂DNA甲基化遗传的影响。【结果】西方蜜蜂(A. mellifera)原有高甲基化位点和突变高甲基化位点均存在表观遗传印迹现象;同时发现随着移虫日龄增加,原有高甲基化位点和突变高甲基化位点遗传印迹数量都是逐步增加;3个调控蜜蜂级型分化的高甲基化遗传印迹模式进一步表明移虫日龄会调控蜂王的高甲基化水平,且蜂王高甲基化位点数目越多,所育雄蜂后代也将获得更多额高甲基化位点。【结论】DNA甲基化遗传印迹能够在西方蜜蜂(A. mellifera)这一模式生物体内稳定遗传,为解析蜜蜂DNA甲基化遗传调控机制提供科学依据。

[Objective]This study aims to explore the epigenetic imprinting of genome-wide methylation in honey bees.[Method]Apis melliferawere used as the model organism in this study.A single male inseminated queen(G0 queen)was used to rear offspring queens(G1 queen).The G1 queen was reared from eggs(E),1-day-old larvae(L1)and 2-day-old larvae(L2),respectively.In G1 generation,G1E represents the queen from eggs.G1L1 represents the queen reared from 1-day-old larvae and G1L2 represents the queen reared from 2-day-old larvae.The three types of G1 queens were further used to breed drones.G2DE represents drones produced by G1E.G2DL1 represents drones produced by G1L2 and G2DL2 represents drones produced by G1L2.The methylated loci in G0 queens,G1 queens and G2 drones were quantified by using the whole genome Bisulfite methylation sequencing.Analysis of variance(ANOVA)and comparison of high-methylation loci was used to reveal the DNA methylation inheritance marks of honeybee(Apis mellifera)and the effect of the aging of larvae for the transplantation on DNA methylation inheritance in honeybee(Apis mellifera).[Result]The results showed that both the highly methylated loci and the mutant methylated loci could be epigenetically inherited.The number of high-methylation and mutant highly methylated loci gradually increased with the aging of larvae for transplantation.Three genetic imprinting patterns of high-methylation that regulated the caste differentiation of honey bees further indicated that the aging of larvae for transplantation would regulate the high-methylation level of the queen.The higher number of high-methylation loci in the queen would make the drones offspring acquire more hypermethylation loci.[Conclusion]The marks of DNA methylation can be stably inherited in the honeybee model organism,thus providing a scientific basis for resolving the genetic regulation mechanism of DNA methylation in honey bees.