Sequence of a gene from Bombina orientalis coding for the antimicrobial peptide BLP-7.

The structure of a gene coding for bombinin-like peptides (BLP) in Bombina orientalis was determined. It comprises two exons separated by a 1337 bp intron. Exon 1 codes for the signal peptide, while exon 2 contains the genetic information for BLP-7 and a bombinin H-type peptide (GH-2). The promoter region contains putative recognition sites for nuclear factors, such as NF-IL6 and NF-kappaB. The analysis of the structure of this gene, compared with that of the previously reported BLP-3 gene sequence, suggests the occurrence of a gene duplication event, rather than an alternative splicing mechanism, which leads to the generation of both inter- and intra-families variability in this class of cytolytic peptides. Furthermore, chromosome walking analysis indicates that this gene family is not densely clustered.