Methyl-CpG binding domain proteins (MBD) can specifically bind to methylated CpG sites and play important roles in epigenetic gene regulation. Here, we identified and functionally characterized the MBD protein in Tribolium castaneum. T. castaneum genome encodes only one MBD protein: TcMBD2/3. RNA interference targeting this gene at different developmental stages caused lethal phenotypes including metamorphosis deficiency in larvae and pupae, gastrointestinal system problems and fecundity deficiency in adult. Moreover, Tcmbd2/3 knockdown adult showed progressive reduced locomoter activity, a typical neurodegeneration phenotype. This is a common feature of DNA methylation in mammals and has not been found in other insects. However, band shift assays demonstrated that TcMBD2/3 could not bind to methylated DNA, indicating the essential roles of TcMBD2/3 is independent of DNA methylation. Our study provides Tcmbd2/3 plays important roles in T. castaneum and gives new insights into the potential mechanism of action of MBD proteins in insect.

甲基CpG结合域蛋白（MBD）可以特异性结合甲基化CpG位点，并在表观遗传基因调控中发挥重要作用。在这里，我们确定了Tribolium castaneum中的MBD蛋白并对其进行了功能表征。赤拟谷盗基因组编码只有一个MBD蛋白：TcMBD2 / 3。针对该基因在不同发育阶段的RNA干扰导致致死表型，包括幼虫和p的变态缺陷，胃肠系统问题和成年生殖力不足。而且，Tcmbd2 / 3击倒的成年人表现出逐渐降低的机车活动，这是典型的神经变性表型。这是哺乳动物DNA甲基化的共同特征，在其他昆虫中尚未发现。但是，带移分析表明TcMBD2 / 3不能与甲基化DNA结合，表明TcMBD2 / 3的基本作用与DNA甲基化无关。我们的研究提供Tcmbd2 / 3起着重要作用，赤拟谷盗，并给出了新的见解昆虫MBD蛋白的作用的潜在机制。