Novel venom gene discovery in the platypus

Abstract

BackgroundTo date, few peptides in the complex mixture of platypus venom have been identified and sequenced, in part due to the limited amounts of platypus venom available to study. We have constructed and sequenced a cDNA library from an active platypus venom gland to identify the remaining components.ResultsWe identified 83 novel putative platypus venom genes from 13 toxin families, which are homologous to known toxins from a wide range of vertebrates (fish, reptiles, insectivores) and invertebrates (spiders, sea anemones, starfish). A number of these are expressed in tissues other than the venom gland, and at least three of these families (those with homology to toxins from distant invertebrates) may play non-toxin roles. Thus, further functional testing is required to confirm venom activity. However, the presence of similar putative toxins in such widely divergent species provides further evidence for the hypothesis that there are certain protein families that are selected preferentially during evolution to become venom peptides. We have also used homology with known proteins to speculate on the contributions of each venom component to the symptoms of platypus envenomation.ConclusionsThis study represents a step towards fully characterizing the first mammal venom transcriptome. We have found similarities between putative platypus toxins and those of a number of unrelated species, providing insight into the evolution of mammalian venom.

Discovery and Characterization of Novel Cyclotides Originated from Chimeric Precursors Consisting of Albumin-1 Chain a and Cyclotide Domains in the Fabaceae Family

“…The toxin genes identified from this animal show striking homology to those found in other venomous species such as snakes, starfish, and sea anemones. Genetic analysis reveals that these venoms have evolved independently from different origins but ended up developing similar families of molecules (55).…”

Multiomics analysis of the giant triton snail salivary gland, a crown-of-thorns starfish predator

“…Metalloproteinases are a family of proteolytic enzymes that are involved in a large number of biological processes. A variety of metalloproteinases are found in the venoms of spiders, scorpions, centipedes, cone snails and the platypus [93][94][95][96][97][98] . In snakes, these enzymes cause hemorrhaging upon envenomation 99 .…”

Ecological venomics: How genomics, transcriptomics and proteomics can shed new light on the ecology and evolution of venom

“…An example for such difficulties can be found in the work of Whittington et al [57] where 454 as well as Illumina NGS platforms were used for sequencing the venom gland of platypus, and the data was compared to older Sanger data for transcripts of this animal's bill, brain, liver, spleen, and testis. The idea was to use the data from the non-venom-related tissues to exclude physiological genes that are not toxins.…”

“…Moreover, venom gland transcriptomic investigations have provided novel insights into the composition and evolution of venom in various poorly studied venomous animals, such as sea anemones, polychaete worms, remipede crustaceans, ticks and platypus[53][54][55][56][57]. The transcriptomic approach is especially important when proteomics are not feasible due to limited venom accessibility.…”