Involvement of Rel factors in the expression of antimicrobial peptide genes in amphibia

Abstract

Genes coding for antimicrobial peptides in amphibia reveal a remarkably high number of structural motifs for response elements, previously identified in the genes of insect antimicrobial peptides and in those of the mammalian acute phase response. This study focuses on the functional analysis of the bombinin gene promoter in a Drosophila blood cell line, and the identification of kB-binding factors in skin secretions of the frog Bombina orientalis. Transfection experiments demonstrated that the bombinin gene promoter was activated in a lipopolysaccharidedependent manner, and that insect Rel factors target specific sequences in the amphibian gene promoter. After bathing frogs in bacteria, their skin secretions contained kB-specific binding complexes, indicating that Rel factors are crucial components in the response against gramnegative bacteria in this species. These results suggest that a common ancestral control mechanism governs the expression of the first line host-defence from insects to vertebrates.

The synthesis of antimicrobial peptides in the skin ofRana esculentais stimulated by microorganisms

“…When the frog is re-exposed to either C. guiller-mondii or natural bacterial flora (data not shown), a strong signal reappears. Similar results were obtained recently using B. orientalis skin secretions (19).…”

Cg‐Rel, the first Rel/NF‐κB homolog characterized in a mollusk, the Pacific oyster Crassostrea gigas

“…Rel proteins have also been identified in birds, fishes, an amphibian, an ascidian, an echinoderm and a leech [35–38]. The latter Rel proteins characterized, as well as proteins found in insects, are mostly known to take part in the innate immune response and development, but a few of them have been functionally characterized or shown to be associated to a NF‐κB‐like pathway [39–42] with one notable exception.…”

Application of ‘Inductive’ QSAR Descriptors for Quantification of Antibacterial Activity of Cationic Polypeptides

“…A diverse population of antimicrobial peptides (AMP-s) can be found in nature, as they are an essential component of anti-infective defence mechanisms in mammals, amphibians, insects and plants [8][9][10][11]. The majority of AMP-s share several key structural features such as short length (typically 10 to 40 amino acids), amphipathicity (i.e., a molecule has distinct cationic and hydrophobic faces), and helical or cyclic structure.…”