Bioinformatic and molecular characterization of beta-defensins-like peptides isolated from the green lizard Anolis carolinensis

The high resistance of lizards to infections indicates that anti-microbial peptides may be involved. Through the analysis of the green lizard (Anolis carolinensis) genome and the expressed sequence tag (EST) libraries 32 beta-defensin-like-peptides have been identified. The level of expression of some of these genes in different tissues has been determined by semi-quantitative RT-PCR. Gene expression and structure analysis suggest the presence of alternative splicing mechanisms, with a number of exons ranging from two to four, similar to that for beta-defensins genes in mammals. Lizard beta-defensin-like peptides present the characteristic cysteine-motif identified in mammalian and avian beta-defensins. Phylogenetic analysis indicates that some lizard beta-defensins-like peptides are related to crotamine and crotamin-like peptides of snakes and lizards suggesting that beta-defensins and venomous peptides have a common ancestor gene.

► Anolis carolinensis genome contains at least 32 beta-defensin-like genes.
► A. carolinensis beta-defensin-like proteins present the characteristics cysteine-motif.
► Gene organization indicates a variable number of exons ranging from two to four.
► Gene expression suggests the presence of alternative splicing mechanisms.
► Some lizard beta-defensin-like proteins are related to crotamine/crotamin-like peptides of snakes and lizards.