基于转录组的分析揭示了昆虫脂肪体在成虫羽化后重建过程中的染色质重塑现象。

doi:10.1016/j.jia.2024.06.018

摘要/Abstract

摘要：

昆虫的脂肪体类似于脊椎动物中的肝脏和脂肪组织，在能量代谢、营养储存及生殖过程中发挥着核心作用。在昆虫变态过程中，脂肪体通过程序性细胞死亡和细胞解离而分解。成虫羽化后，脂肪体通过剩余幼虫脂肪细胞的增殖或成体干细胞的分化而重建。这一重建过程是合成大量卵黄原蛋白（Vg）的前提条件，Vg对于多个卵子的成熟至关重要。尽管其重要性显而易见，但分子机制仍未得到充分解析。通过对羽化后0-5天蝗虫脂肪体的转录组分析，揭示了79个与染色质重塑相关的基因。加权基因共表达网络分析（WGCNA）表明，染色质重塑与脂肪体重建呈正相关。蛋白质-蛋白质相互作用分析（PPI）显示，编码SWI/SNF染色质重塑复合体催化亚基的brahma基因对于成虫羽化后脂肪体的发育至关重要。qRT-PCR分析证明，brahma mRNA在卵黄生成前期在脂肪体中的水平逐渐升高，随后达到峰值并在卵黄生成期保持高水平。此外，brahma响应保幼激素（JH）而表达。brahma敲低导致脂肪体内Vg表达显著减少，并伴有卵巢生长停滞。研究结果阐明了brahma介导的染色质重塑在JH依赖的脂肪体重建及雌性昆虫生殖中的作用机制。

Abstract:

The insect fat body is comparable to the liver and adipose tissue in vertebrates, and plays a pivotal role in energy metabolism, nutrient storage, and reproduction. During metamorphosis, the fat body is disassembled via programmed cell death and cell dissociation. After adult eclosion, the fat body is reconstructed either by repopulation from the remaining juvenile fat body cells or by differentiation from adult progenitor cells. This reconstruction is a prerequisite for initiating the extensive synthesis of vitellogenin (Vg), which is necessary for the maturation of eggs. Despite its significance, the underlying mechanisms of this reconstruction remain inadequately understood. Transcriptome analysis of the fat bodies from migratory locusts at 0–5 days post adult emergence revealed 79 genes associated with chromatin remodeling. Weighted gene co-expression network analysis indicated a positive correlation between chromatin remodeling and fat body reconstitution. Protein–protein interaction analysis revealed that brahma, which encodes the catalytic subunit of the SWI/SNF chromatin remodeling complex, is crucial for post-adult-eclosion fat body development. qRT-PCR analysis demonstrated that the levels of brahma mRNA in the fat body are progressively increased during the previtellogenic stage, then reach the peak and remain elevated in the vitellogenic phase. Furthermore, brahma is expressed in response to gonadotropic juvenile hormone (JH). Knockdown of brahma led to a marked reduction in Vg expression within the fat body, along with arrested ovarian growth. These findings shed light on the involvement of brahma-mediated chromatin remodeling in JH-stimulated fat body reconstruction and reproduction of adult female locusts.

Key words: fat body reconstruction , transcriptome analysis , chromatin remodeling , juvenile hormone , female reproduction

. 基于转录组的分析揭示了昆虫脂肪体在成虫羽化后重建过程中的染色质重塑现象。[J]. Journal of Integrative Agriculture, 2025, 24(2): 668-679.

Yiying Li, Yuanyuan Hu, Bei Wang, Mengyao Lang, Shutang Zhou, Zhongxia Wu. Transcriptome-based analysis reveals chromatin remodeling in post-adult eclosion reconstruction of the insect fat body[J]. Journal of Integrative Agriculture, 2025, 24(2): 668-679.

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