Sci. Signal., 9 August 2011
Sensory Perception Vampire Senses
Nancy R. Gough
Science Signaling, AAAS, Washington, DC 20005, USA
Vampire bats, like heat-sensing snakes, have specialized organs that allow them to detect infrared radiation (heat) (see Fenton). In vampire bats, these are located around the nose, and, in both heat-sensing organisms, the sensory ganglia (trigeminal ganglia) receiving the input from these organs exhibit anatomical differences from those in their nonheat-sensing brethren. Gracheva et al. report another critical difference between vampire bats and fruit bats. Deep sequencing revealed a variant form of the transient receptor potential V1 (TRPV1) channel in vampire bats, and this variant lacked 62 amino acids of the C terminus. Analysis of the heat activation characteristics of this channel in transfected cells and mRNA-injected oocytes indicated that the TRPV1-S (short variant) exhibited a lower temperature threshold than the TRPV1-L (long variant): TRPV1-S had an activation threshold of ~30°C and TRPV1-L of ~40°C. The production of the short variant was due to the inclusion of a small exon (14a) containing a stop codon. The authors used genomic comparisons of this region to show that cows, moles, and dogs, but not rodents or humans, had 14a exons like that of the vampire bat. However, the production of this splice variant was less than 6% of the detectable TRPV1 transcripts in mole or cow trigeminal ganglia, suggesting that splicing to include this exon requires a specific cellular environment found in the vampire bat. This analysis also supports the classification along the tree of life of bats as more closely related to cows, horses, dogs, dolphins, and moles than to primates and rodents. Heat-sensing snakes use another member of the TRP family, the TRPA1 channel, and as noted by Gracheva et al., zebrafish also exhibit divergence of the C terminal of the TRPV1 channel to produce a channel activated at ~32°C. However, this variant is different from the one in bats, and sequence analysis indicated that it occurred through a polymorphism in exon 15. Thus, thermosensory adaption has occurred through different molecular mechanisms.
E. O. Gracheva, J. F. Cordero-Morales, J. A. González-Carcacia, N. T. Ingolia, C. Manno, C. I. Aranguren, J. S. Weissman, D. Julius, Ganglion-specific splicing of TRPV1 underlies infrared sensation in vampire bats. Nature 476, 88–91 (2011). [PubMed]
M. B. Fenton, Heat-thirsty bats. Nature 476, 40–41 (2011). [PubMed]
Citation: N. R. Gough, Vampire Senses. Sci. Signal. 4, ec219 (2011).
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