THESIS
2018
xvii, 220, that is, xvii, 226 pages : illustrations (some color) ; 30 cm
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, m...[
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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.
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