A novel lipocalin homologue from the venom gland of Deinagkistrodon acutus similar to mammalian lipocalins

• Autor(a) principal: Wei,CB
• Data de Publicação: 2012
• Outros Autores: Chen,J
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: The Journal of venomous animals and toxins including tropical diseases (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1678-91992012000100003
• topic: Deinagkistrodon acutus; cDNA library; lipocalin; phylogeny; gene expression pattern analysis

Lipocalins are involved in a variety of functions including retinol transport, cryptic coloration, olfaction, pheromone transport, prostaglandin synthesis, regulation of the immune response and cell homeostatic mediation. A full-length cDNA clone (named d-lipo), isolated from the venom gland cDNA library of Deinagkistrodon acutus, contained an insert of 664 bp including an open reading frame that encodes a lipocalin homologue of 177 amino acids. Comparison of d-lipo and other related proteins revealed an overall amino acid identity of less than 21.5%. Primary structures of d-lipo carried three structurally conserved regions (SCR) showing homologies to those of lipocalins. The first conserved Cys residue - the essential amino acid residue for the catalytic activity and unique to lipocalin-type prostaglandin D synthase (L-PGDS) in the lipocalin protein family - was identified in d-lipo at amino acid position 58. Phylogenetic tree analysis showed that d-lipo was in-between the large L-PGDS cluster and the small von Ebner's-gland proteins (VEGP) cluster. Moreover, d-lipo gene presented a high-level expression in the venom gland and a low-level expression in the brain and its expression was significantly increased under pathological conditions, suggesting a possible relationship between d-lipo mRNA expression and the venom gland inflammatory disease. This is also the first report of a lipocalin homologous gene identified in the venom gland of a snake.