Properties of the Bombyx mori insulin-like peptide (BmILP) gene

Insulin/Insulin-like growth factors play important roles in promoting proliferation, differentiation, growth and development of organisms. In this article, bioinformatics analysis was performed to locate and identify the Bombyx mori insulin-like peptide (BmILP) gene, which had two introns, three exons, and a predicted signal peptide at the front, and it also determined that BmILP was the same to the gene Bombyxin Z1, a member of the bombyxin family. Both the full-length BmILP gene and the gene without the signal peptide expressed mainly existed in inclusion body forms at different induction conditions and it was noted that the signal peptide had significant influence on the expression level. In addition, protein-protein interaction experiments suggested that there was interaction between BmILP and the autophagy-related protein Atg8, indicating that BmILP may play a role in immunity. It was found was that BmILP predominantly produced by the ovary among different tissues in the silkworm. Particularly, the adult females had higher expression levels than the adult males, and the expression level appeared to be the highest in the mated female moths, suggesting that BmILP may be a key factor in the regulation of egg maturation in Bombyx mori.