Abstract：
Silkworm fibroins are natural proteinaceous macromolecules and provide core mechanical properties to silk fibers. The synthesis process of fibroins is posterior silk gland (PSG)-exclusive and appears active at the feeding stage and inactive at the molting stage. However, the molecular mechanisms controlling it remain elusive. Here, the silk gland\'s physiological and nuclear proteomic features were used to characterize changes in its structure and development from molting to feeding stages. The temporal expression profile and immunofluorescence analyses revealed a synchronous transcriptional on-off mode of fibroin genes. Next, the comparative nuclear proteome of the PSG during the last molting-feeding transition identified 798 differentially abundant proteins (DAPs), including 42 transcription factors and 15 epigenetic factors. Protein-protein interaction network analysis showed a \"CTCF-FOX-HOX-SOX\" association with activated expressions at the molting stage, suggesting a relatively complex and multifactorial regulation of the PSG at the molting stage. In addition, FAIRE-seq verification indicated \"closed\" and \"open\" conformations of fibroin gene promoters at the molting and feeding stages, respectively. Such proteome combined with chromatin accessibility analysis revealed the detailed signature of protein factors involved in the temporal regulation of fibroin synthesis and provided insights into silk gland development as well as silk production in silkworms.
摘要：
蚕丝素是天然的蛋白质大分子，为蚕丝纤维提供核心机械性能。丝纤蛋白的合成过程是后丝腺（PSG）专有的，并且在进食阶段表现出活性，而在蜕皮阶段则不活跃。然而,控制它的分子机制仍然难以捉摸。这里,丝腺的生理和核蛋白质组特征被用来表征其结构和发育从蜕皮到摄食阶段的变化。时间表达谱和免疫荧光分析揭示了丝心蛋白基因的同步转录开关模式。接下来,PSG在最后一次蜕皮-摄食过渡期间的比较核蛋白质组鉴定出798种差异丰富的蛋白质（DAP），包括42个转录因子和15个表观遗传因子。蛋白质-蛋白质相互作用网络分析显示“CTCF-FOX-HOX-SOX”与蜕皮阶段的激活表达相关，表明PSG在蜕皮阶段相对复杂和多因素的调节。此外,FAIRE-seq验证表明，在蜕皮和摄食阶段，丝心蛋白基因启动子的“封闭”和“开放”构象。分别。这种蛋白质组与染色质可及性分析相结合，揭示了与丝素蛋白合成的时间调节有关的蛋白质因子的详细特征，并提供了有关蚕丝腺发育和丝生产的见解。
