Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, 030006, China.
Insect Sci. 2022 Feb;29(1):51-64. doi: 10.1111/1744-7917.12907. Epub 2021 Feb 25.
Halloween genes are involved in the biosynthesis of the molting hormone, which plays a key role in insect ecdysis, development, metamorphosis, and reproduction. Our previous work identified five Halloween genes from Locusta migratoria, but their functions are currently unknown. In this study, the sequences of these five Halloween genes were analyzed and characterized. LmCYP307a2, LmCYP306a1, LmCYP302a1, and LmCYP315a1 were primarily expressed in the prothoracic glands, while LmCYP314a1 was universally expressed in peripheral tissues, especially in the ovaries and Malpighian tubules. All five Halloween genes were mainly expressed from the 5th to the 7th d in 5th-instar nymphs. RNA interference (RNAi) silencing of LmCYP307a2 resulted in severe molting delays and molting failure, which could be rescued by supplementary 20-hydroxyecdysone. A hematoxylin and eosin staining analysis suggested that the RNAi of LmCYP307a2 inhibited the ecdysis process by inhibiting the apolysis and degradation of the old cuticle, and by promoting the synthesis of a new cuticle. Quantitative reverse transcription polymerase chain reaction results showed that the expressions of LmE74, LmCht5, and LmCht10 were dramatically down-regulated, while that of LmChsI was substantially up-regulated, after knockdown of LmCYP307a2. The results suggest that LmCYP307a2 is related to the molt process via regulation of chitin synthesis and degradation.
万圣节基因参与蜕皮激素的生物合成，蜕皮激素在昆虫蜕皮、发育、变态和生殖中起着关键作用。我们之前的工作从飞蝗中鉴定了五个万圣节基因，但它们的功能目前尚不清楚。在这项研究中，分析和表征了这五个 Halloween 基因的序列。LmCYP307a2、LmCYP306a1、LmCYP302a1 和 LmCYP315a1 主要在前胸腺中表达，而 LmCYP314a1 在周围组织中普遍表达，特别是在卵巢和马氏管中。这五个 Halloween 基因在 5 龄若虫的第 5 至第 7 天主要表达。LmCYP307a2 的 RNA 干扰 (RNAi) 沉默导致严重的蜕皮延迟和蜕皮失败，补充 20-羟基蜕皮酮可挽救这种情况。苏木精和伊红染色分析表明，LmCYP307a2 的 RNAi 通过抑制旧表皮的解体和降解以及促进新表皮的合成来抑制蜕皮过程。定量逆转录聚合酶链反应结果表明，LmE74、LmCht5 和 LmCht10 的表达显著下调，而 LmChsI 的表达显著上调，在敲低 LmCYP307a2 后。结果表明，LmCYP307a2 通过调节几丁质的合成和降解与蜕皮过程有关。
