Identification of nematodes volatile sex pheromone functional components and the molecular basis of sex pheromone perception

Abstract

Our lab studies the molecular basis of chemosensory behaviors. Sexually mature C. remanei females and self-sperm exhausted C. elegans hermaphrodites produce an attractant detectable by adult C. remanei and C. elegans males. This volatile attractant acts in a sex-, stage- and species-specific manner and thus qualifies as a long-range sex pheromone. We are searching for the corresponding receptors in C. elegans. Previously, we reported the result of cell ablation experiments that demonstrated the importance of CEM, AWA, and AIZ neurons in the perception of sex pheromones. In AWA, SRD-1 was identified as a GPCR responding to the sex pheromone perception of C. remanei females and C. elegans hermaphrodites; this finding was corroborated by localization, single-cell microarray data, mutation strain function examinations, and cell-specific cDNA rescue experiments. Ectopic expression of srd-1 in AWB would lead to a repulsive behavioral response. In addition, the requirement of the SRD-1 receptor in the excitability of AWA neurons in response to both the sex pheromones of C. remanei females and C. elegans hermaphrodites was identified by means of a calcium imaging experiment. Furthermore, we demonstrated that the C-terminal region in SRD-1 confers species-specific differential sex pheromone perception between C. elegans and C. remanei. These findings offer a good model for dissecting how a single chemical cue coupled with a dimorphic neural system contributes to sex-specific behaviors in animals. Analysis of C. remanei females’ attractant GC-MS data suggested the presence of several chemicals, two of which are functionally verified by chemo-attraction assays. Intriguingly, the two pheromone candidates above could not attract the olfactory pathway mutant strain related to the sex pheromone perception pathway. srd-1 mutant males lose the ability to sense the two pheromone candidates. Hexenyl acetate can excite the AWA neurons of wild-type males, but not srd-1 mutant males. This result further strengthens the possibility of a link between the suggested ligands and receptor.

Date of Award	2018
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology