Functional characterization of a previously unknown gene governing metamorphosis in Bombyx mori

Insect metamorphosis is a highly complex biological process, particularly during the transition from larva to pupa, involving the precise and coordinated regulation of multiple genes and pathways. However, the functions and regulatory mechanisms of numerous critical genes in this process remain poorly understood. In this study, a previously uncharacterized gene, Lptf, was identified in Bombyx mori. Tissue expression analysis revealed that this gene is widely expressed across different tissues. Lptf mutants were generated using a binary transgenic CRISPR/Cas9 system. Disruption of Lptf led to a significant decrease in larval body size, as well as reduced triacylglycerol (TAG) content. Furthermore, deletion of Lptf resulted in failure of the larval-pupal metamorphosis and impaired silk gland development and silk production. RNA-seq and qRT-PCR analyses indicated that mutation of Lptf caused significant downregulation of 20-hydroxyecdysone response genes and silk protein genes. KEGG pathway enrichment analysis revealed significant enrichment of the spliceosome pathway, and GO enrichment analysis showed significant enrichment of RNA processing, suggesting that RNA splicing and processing are markedly affected. These findings not only reveal a previously uncharacterized gene involved in metamorphosis but also provide important insights into further deciphering the gene regulatory network underlying insect metamorphosis.