biostudies-literatureWang YScientific and Technological Research Program of Chongqing Municipal Education CommissionNational Natural Science Foundation of Chinae1011837https://www.ebi.ac.uk/biostudies/studies/S-EPMC12380352biostudies-literatureUnknown21(8)Insects undergo periodic ecdysis to shed their old chitinous exoskeleton and form a new cuticular layer. The steroid hormone 20-hydroxyecdysone (20E) is widely recognized as a central regulator of insect molting. Acting as a signaling molecule, 20E pulses orchestrate gene expression in a concentration- and time-dependent fashion. However, investigations into the transcriptomic and epigenomic alterations linked to dynamic 20E fluctuations remain limited. In this study, we explored the temporal dynamics of epidermal transcriptomes and genome-wide chromatin accessibility during the larval-larval molting cycle of the silkworm, Bombyx mori. Our results unveiled pronounced shifts in gene expression and chromatin architecture between early and late molting stages, correlating with ascending and dPLoS geneticsTranscriptomic landscape and chromatin accessibility uncover pivotal regulators driving programmed larval-larval molting in the domesticated silkworm.PMC1238035231772527KJZD-K20220050732070499Yang XLing XZhang ZHong JSun WWang YLi LQiao LfalseTranscriptomic landscape and chromatin accessibility uncover pivotal regulators driving programmed larval-larval molting in the domesticated silkworm.Insects undergo periodic ecdysis to shed their old chitinous exoskeleton and form a new cuticular layer. The steroid hormone 20-hydroxyecdysone (20E) is widely recognized as a central regulator of insect molting. Acting as a signaling molecule, 20E pulses orchestrate gene expression in a concentration- and time-dependent fashion. However, investigations into the transcriptomic and epigenomic alterations linked to dynamic 20E fluctuations remain limited. In this study, we explored the temporal dynamics of epidermal transcriptomes and genome-wide chromatin accessibility during the larval-larval molting cycle of the silkworm, Bombyx mori. Our results unveiled pronounced shifts in gene expression and chromatin architecture between early and late molting stages, correlating with ascending and d2025-01-01T00:00:00Z2025 Aug2026-05-10T04:24:44.189Z2026-04-08T01:28:46.354ZS-EPMC123803524082886510.1371/journal.pgen.1011837