PT  - JOURNAL ARTICLE
AU  - Lina Ni
AU  - Mason Klein
AU  - Kathryn Svec
AU  - Gonzalo Budelli
AU  - Elaine C. Chang
AU  - Richard Benton
AU  - Aravinthan D. T. Samuel
AU  - Paul A. Garrity
TI  - The Ionotropic Receptors IR21a and IR25a mediate cool sensing in <em>Drosophila</em>
AID  - 10.1101/032540
DP  - 2015 Jan 01
TA  - bioRxiv
PG  - 032540
4099  - http://biorxiv.org/content/early/2015/11/22/032540.short
4100  - http://biorxiv.org/content/early/2015/11/22/032540.full
AB  - Animals rely on highly sensitive thermoreceptors to seek out optimal temperatures, but the molecular mechanisms of thermosensing are not well understood. The Dorsal Organ Cool Cells (DOCCs) of the Drosophila larva are a set of exceptionally thermosensitive neurons critical for larval cool avoidance. Here we show that DOCC cool-sensing is mediated by Ionotropic Receptors (IRs), a family of sensory receptors widely studied in invertebrate chemical sensing. We find that two IRs, IR21a and IR25a, are required to mediate DOCC responses to cooling and are required for cool avoidance behavior. Furthermore, we find that ectopic expression of IR21a can confer cool-responsiveness in an Ir25a-dependent manner, suggesting an instructive role for IR21a in thermosensing. Together, these data show that IR family receptors can function together to mediate thermosensation of exquisite sensitivity.