Structure of genes for cecropin A and an inducible nuclear protein that binds to the promoter region of the genes from the silkworm, Bombyx mori

Cecropins are a family of antibacterial peptide synthesized in insects as a response to bacterial infection. To study the regulation of the immune genes in insects, two cecropin A genes were cloned and sequenced from the silkworm, Bombyx mori. The two genes, CecA1 and CecA2, encoded identical preprocecropin A, having one intron of 609 bp and 929 bp, respectively. The 5'-upstream regions of the genes contained a NF-kappa B like element and IL-CRE Type I element. Electrophoretic mobility shift assay revealed that a nuclear protein of fat body which specifically bound to the kappa B-like element was activated by injection of the larvae with peptidoglycan.