The fish-hunting cone snail, Conus geographus, is the deadliest snail on earth. In the absence of medical intervention, 70% of human stinging cases are fatal. Although, its venom is known to consist of a cocktail of small peptides targeting different ion-channels and receptors, the bulk of its venom constituents, their sites of manufacture, relative abundances and how they function collectively in envenomation has remained unknown.
Researchers at the University of Utah have used RNA-Seq to systemically elucidate the contents the C.geographus venom duct, dividing it into four segments in order to investigate each segment’s mRNA contents. Three different types of Calcium channel (each targeted by unrelated, entirely distinct venom peptides) and at least two different nicotinic receptors appear to be targeted by the venom. Moreover, the most highly expressed venom component is not paralytic, but causes sensory disorientation and is expressed in a different segment of the venom duct from venoms believed to cause sensory disruption. They have also identified several new toxins of interest for pharmaceutical and neuroscience research.
This transcriptome analysis provides a new physiological framework for understanding the molecular envenomation strategy of this deadly snail.
- Hu H,Bandyopadhyay PK, Olivera BM, Yandell M. (2012) Elucidation of the molecular envenomation strategy of the cone snail conus geographus through transcriptome sequencing of its venom duct. BMC Genomics 13:284. [article]