Hussain, A., Saraiva, L.R., Ferrero, D.M., Ahuja, G., Krishna, V.S., Liberles, S.D., and Korsching, S.I. (2013) High-affinity olfactory receptor for the death-associated odor cadaverine. Proc. Natl. Acad. Sci. USA. 110(48):19579-19584.
Carrion smell is strongly repugnant to humans and triggers distinct innate behaviors in many other species. This smell is
mainly carried by two small aliphatic diamines, putrescine and cadaverine, which are generated by bacterial decarboxylation
of the basic amino acids ornithine and lysine. Depending on the species, these diamines may also serve as feeding attractants,
oviposition attractants, or social cues. Behavioral responses to diamines have not been investigated in zebrafish, a powerful
model system for studying vertebrate olfaction. Furthermore, olfactory receptors that detect cadaverine and putrescine have
not been identified in any species so far. Here, we show robust olfactory-mediated avoidance behavior of zebrafish to cadaverine
and related diamines, and concomitant activation of sparse olfactory sensory neurons by these diamines. The large majority
of neurons activated by low concentrations of cadaverine expresses a particular olfactory receptor, trace amine-associated
receptor 13c (TAAR13c). Structure-activity analysis indicates TAAR13c to be a general diamine sensor, with pronounced selectivity
for odd chains of medium length. This receptor can also be activated by decaying fish extracts, a physiologically relevant
source of diamines. The identification of a sensitive zebrafish olfactory receptor for these diamines provides a molecular
basis for studying neural circuits connecting sensation, perception, and innate behavior.