Characterization of snake venom metalloproteinase toxin genes from Bothrops jararaca

Abstract

The analysis of molecular evolution of snake toxins performed so far generally lacks basic genomic information as background. Duplications, insertions and intron deletions appears to be more important than random point mutations for the diversification of the snake venom metalloproteinase (SVMP), as recently described on Echis ocellatus genes. In this sense, we proposed in this posdoc to deeply characterize the Bothrops jararaca SVMP genes, an ancestral toxin type present in all Viperidae snakes, to reconstruct their evolutionary history. SVMP constitute a diversified family of toxins classified according to their modular domain composition. Their sequences and domain composition clearly indicates they are part of the ADAM family of transmembrane proteins and apparently the SVMPs have originated from the ADAM28 gene. Our genomic data corroborates this hypothesis and shows that SVMP is a multigenic family organized in tandem over a long single stretch of the genome. Although accurate, our short-reads sequences could not overcome large repetitive elements, precluding a more detailed view of this gene cluster. Hence, we propose (1) to obtain long-read sequences of these genes using MinION, a 3rd generation DNA sequencer from Oxford Nanopore Technology, available at Dr. Calvete's lab, and (2) characterize and analyze previous and new genomic data with Dr. Calvete in order to elaborate hypotheses about the rise and evolution of these genes.