Page 80 - Q. Neuroscience

[Q. Neuroscience-49]

The chemosensory GPCR SRI-14 is required for

concentration-dependent DMTS odor preference in C.

elegans

Woochan Choi¹, Kyuhyung Kim¹

¹Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea

Previous genetic and behavioral experiments have identified set of signaling genes including olfactory receptors in
C. elegans, but the knowledge is still limited. Dimethyl trisulfide (DMTS) is an organic chemical, which smells like
garlic and is derived from bacterial decomposition. Here, we showed that C. elegans attracts to low concentration

of DMTS via the AWC neurons and avoids to high concentration of DMTS via the ASH neurons. We then performed
candidate gene search and found that chemosensory GPCR sri-14 is required for both attraction to low

concentration of DMTS and aversion to high concentration of DMTS. The defects of DMTS chemotaxis in sri-14
mutants were restored when we expressed the wild-type sri-14 gene to the AWC and ASH neurons for attraction

and avoidance, respectively. Ca2+ responses of AWC and ASH upon acute exposure to DMTS is decreased in sri-14
mutants. Furthermore, we heterologously expressed the SRI-14 receptor in the mammalian cell, and found that

these cells confer dose-dependent response upon DMTS exposure, suggesting that SRI-14 is indeed a bona fide
DMTS receptor. Next, we found that the AIB interneurons, receiving signals from AWC and ASH neurons, exhibit

distinct Ca2+ responses depending upon the concentration of DMTS.