A novel member of the bombyxin gene family: structure and expression of bombyxin G1 gene, an insulin-related peptide gene of the silkmoth Bombyx mori

Bombyxin G1 gene, a novel insulin-related peptide gene of the silkmoth Bombyx mori, has been identified. The G1 gene encodes a precursor peptide which shows 41-56% and 28% sequence identities with preprobombyxins previously characterized and human preproinsulin, respectively. The G1 gene forms a pair with bombyxin C2 gene with opposite transcriptional orientation in a bombyxin gene cluster. The bombyxin G1 mRNA in Bombyx brain was shown to locate in four pairs of medial neurosecretory cells.