Molecular cloning of a bombinin gene from Bombina orientalis: detection of NF-kappaB and NF-IL6 binding sites in its promoter.

The sequence of a gene from Bombina orientalis was determined which codes for antibacterial peptides. The gene comprises two exons separated by a large intron. Exon 1 codes for the signal peptide, while exon 2 contains the genetic information for two identical bombinins and one bombinin H. The promoter region of the bombinin gene contains putative recognition sites for nuclear factors, such as NFkappaB and NF-IL6. In vivo experiments on B. orientalis have shown that a short contact with bacteria is sufficient to induce a marked increase in the amount of antibacterial peptides in the skin secretion of frogs. This increase was suppressed by pretreatment with glucocorticoids. In the latter case, a significant increase of I kappaB alpha in the secretion is also detectable.