Knockdown of Broad-Complex Gene Expression of Bombyx mori by Oligopyrrole Carboxamides Enhances Silk Production

Bombyx mori (B. mori) is important due to its major role in the silk production. Though DNA binding ligands often influence gene expression, no attempt has been made to exploit their use in sericulture. The telomeric heterochromatin of B. mori is enriched with 5′-TTAGG-3′ sequences. These sequences were also found to be present in several genes in the euchromatic regions. We examined three synthetic oligopyrrole carboxamides that target 5′-TTAGG-3′ sequences in controlling the gene expression in B. mori. The ligands did not show any defect or feeding difference in the larval stage, crucial for silk production. The ligands caused silencing of various isoforms of the broad-complex transcription factor and cuticle proteins which resulted in late pupal developmental defects. Furthermore, treatment with such drugs resulted in statistically enhanced cocoon weight, shell weight, and silk yield. This study shows for the first time use of oligopyrrole carboxamide drugs in controlling gene expression in B. mori and their long term use in enhancing silk production.