Sex-specific differences in neuronal gene expression have been identified in a number of animal species, although the significance of these expression differences, in many cases, remains unclear. We have observed a sex-specific modulation in the expression pattern of the TGFß ligand, DAF-7, in male C. elegans.
daf-7 is expressed normally in the ASI neuron pair and is known to regulate many aspects of C. elegans physiology, development and behavior. Recently, our lab has described the induction of
daf-7 expression in an additional pair of chemosensory neurons, the ASJ neurons, in response to exposure to the pathogen Pseuodomonas aeruginosa and defined a role for this expression change in producing a pathogen avoidance behavior (Meisel, JD et. al., Cell, 2014). While hermaphrodites induce expression of
daf-7 in ASJ in the presence of P. aeruginosa, we have observed that males exhibit
daf-7 expression in the ASJ neuron pair in the absence of pathogen. This sexually dimorphic expression occurs stage-specifically in adult males, suggesting a possible role for this expression change in guiding male sexual behaviors or physiology. We have evidence to suggest that
daf-7 expression may be involved in promoting male mate-searching/food leaving behavior and are currently working to further define the role of this sexually dimorphic expression pattern as it pertains to behavior. .