Jiao Yaoyu, Sengodan Karthi, Chen Jiasheng, Palli Subba Reddy
Department of Entomology, Martin-Gatton College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, 40546, USA.
Department of Entomology, Martin-Gatton College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, 40546, USA.
Insect Biochem Mol Biol. 2025 May;180:104316. doi: 10.1016/j.ibmb.2025.104316. Epub 2025 Apr 24.
Methylation levels of core histones play important roles in the regulation of gene expression and impact animal development. However, the methyltransferases and demethylases that determine histone methylation levels remain largely unexplored in insects. Most of our current understanding of histone methylation comes from mammalian studies. In this study, we first identified potential histone methyltransferases and demethylases encoded in the genome of the red flour beetle Tribolium castaneum. The function of these histone methylation enzymes in the metamorphosis was investigated by knocking down genes coding for these enzymes using RNA interference (RNAi). Our results showed that a lysine methyltransferase, KMT5A, plays a critical role in T. castaneum metamorphosis by regulating the biosynthesis of ecdysteroids. Treating KMT5A-knockdown larvae with 20 hydroxyecdysone can partially rescue T. castaneum pupation. Western blot analysis showed that KMT5A catalyzes H4K20 mono-methylation. However, further studies suggest that KMT5A may regulate T. castaneum pupation through mechanisms independent of H4K20 methylation. These data uncovered the roles of histone methylation enzymes in T. castaneum metamorphosis and KMT5A as a critical regulator of ecdysteroid biosynthesis.
核心组蛋白的甲基化水平在基因表达调控和影响动物发育过程中发挥着重要作用。然而，在昆虫中，决定组蛋白甲基化水平的甲基转移酶和去甲基化酶在很大程度上仍未被探索。我们目前对组蛋白甲基化的大多数了解来自哺乳动物研究。在本研究中，我们首先在赤拟谷盗（Tribolium castaneum）的基因组中鉴定出潜在的组蛋白甲基转移酶和去甲基化酶。通过使用RNA干扰（RNAi）敲低编码这些酶的基因，研究了这些组蛋白甲基化酶在变态过程中的功能。我们的结果表明，一种赖氨酸甲基转移酶KMT5A通过调节蜕皮激素的生物合成，在赤拟谷盗的变态过程中发挥关键作用。用20-羟基蜕皮酮处理KMT5A敲低的幼虫可以部分挽救赤拟谷盗的化蛹。蛋白质免疫印迹分析表明，KMT5A催化H4K20单甲基化。然而，进一步的研究表明，KMT5A可能通过独立于H4K20甲基化的机制调节赤拟谷盗的化蛹。这些数据揭示了组蛋白甲基化酶在赤拟谷盗变态过程中的作用以及KMT5A作为蜕皮激素生物合成的关键调节因子的作用。
