1 Brain Science Institute, Tamagawa University, Tamagawagakuen, Machida, Tokyo 194-8610.
J Insect Sci. 2011;11:74. doi: 10.1673/031.011.7401.
The European honeybee, Apis mellifera L. (Hymenoptera: Apidae), has a full set of machinery for functional CpG methylation of its genome. A recent study demonstrated that DNA methylation in the honeybee is involved in caste differentiation. In this study, the expression and methylation of the hexamerin 110 gene (Hex110), which encodes a storage protein, was analyzed. High levels of the Hex110 transcript were expressed in both worker and queen larvae. Low levels of this transcript were also detected in adult fat bodies, and the expression level was higher in the queen than in the worker. Bisulfite sequencing revealed that the Hex110 gene is overall methylated at a low level, with a limited number of CpG sites methylated at relatively high levels. These highly methylated sites were exclusively located in the exon regions. The average methylation rate of the Hex110 gene was higher in the adult stage than in the larval stage. Furthermore, several CpG sites were differentially methylated between the worker and queen larvae. These observations suggest that the methylation of the Hex110 gene is regulated at the developmental stage and in a caste-dependent manner.
欧洲蜜蜂，Apis mellifera L.（膜翅目：蜜蜂科），拥有一套完整的基因组功能 CpG 甲基化机制。最近的一项研究表明，蜜蜂的 DNA 甲基化参与了蜂群分化。在这项研究中，分析了编码贮存蛋白的 hexamerin 110 基因（Hex110）的表达和甲基化。高水平的 Hex110 转录本在工蜂和蜂王幼虫中都有表达。在成年脂肪体中也检测到这种转录本的低水平表达，且在蜂王中比在工蜂中的表达水平更高。亚硫酸氢盐测序显示，Hex110 基因整体呈低甲基化状态，少数 CpG 位点呈相对高水平甲基化。这些高度甲基化的位点仅位于外显子区域。Hex110 基因在成年期的平均甲基化率高于幼虫期。此外，工蜂和蜂王幼虫之间有几个 CpG 位点存在差异甲基化。这些观察结果表明，Hex110 基因的甲基化受到发育阶段和蜂群分化的调控。
