Identification of a high-activity and ubiquitous promoter from lepidoptera insect for transgenic applications

The domesticated silkworm, Bombyx mori, represents a pivotal lepidopteran model for functional genomics and genetic engineering. Despite its utility, the limited repertoire of characterized endogenous promoters constrains advanced genetic manipulation in this species. Here, we report the discovery and functional validation of BmOvoP, a novel 1,206-bp endogenous promoter derived from the BmOvo locus. Transgenic B. mori expressing enhanced green fluorescent protein (EGFP) under BmOvoP regulation exhibited sustained, pan-tissue fluorescence from embryogenesis to adulthood, defining its utility as a developmentally stable, high-efficiency promoter. Quantitative assays in both BmN cell cultures and transgenic lines confirmed robust, ubiquitous EGFP expression, including robust activity in gonads, a historically challenging target for constitutive promoters. Lepidoptera insects exhibit a remarkable diversity of species, yet research on universal and tissue-specific promoters remains limited. Here, we report that BmOvoP's functionality was conserved in the agriculturally significant lepidopteran pest Ostrinia furnacalis, demonstrating cross-species compatibility. This work establishes BmOvoP as a versatile genetic tool for B. mori and related Lepidoptera, addressing a critical gap in lepidopteran transgenics.