125 Oral - Reproduction and Gametogenesis
Friday April 08, 5:45 PM - 6:00 PM

Authors:
Sofie Delbare; Sara Venkatramen; Martin Wells; Sumanta Basu; Mariana Wolfner; Andrew Clark

Affiliation: Cornell University

Keywords:
h. sex-specific traits and molecules; n. networks

Sex Peptide (SP), a seminal fluid protein of D. melanogaster males, elicits an array of post-mating responses in females, including increased egg laying, activity and food intake, with a preference for proteins and a switch from carbohydrate to amino acid metabolism. To determine how one protein can have such widespread effects, we set out to dissect the genetic architecture of the female’s response to SP, and determine whether SP alters the expression of several regulators targeted to specific post-mating responses or acts on a pleiotropic regulator that controls multiple responses. We performed bulk RNA-seq of female heads at 10 time points within the first 24 hours after mating, sampling virgin females, females mated to control males and females mated to SP-null males. Using gene- and exon-level differential expression (DE) analyses, we find 666 genes and 86 exons that are DE across the 3 treatments. The earliest DE features include 3 regulators of circadian rhythms (cwo, Clk, Pdp1), leading us to hypothesize that SP acts on the circadian clock to induce at least a subset of post-mating responses. Consistent with this, we find that 16% of the 752 DE features have circadian expression patterns in virgin females, and their rhythms are altered after mating. Cluster analysis shows that features with altered circadian rhythms follow either of two patterns: upregulated during both day and night, or downregulated specifically during the night, relative to virgin females and females that did not receive SP. The downregulated genes include ones involved in glycogen biosynthesis, transcription factors involved in energy metabolism, and Acer, whose downregulation is known to cause increased activity at night. Upregulated genes include ones involved in amino acid metabolism, transcription factors including Clk, and signaling molecules. Among these are exons of foraging, a well-studied gene with roles in feeding behavior, of which some exons follow a circadian rhythm in virgin females, but no longer after receipt of SP. Overall, our transcriptome analysis suggests that SP might act on genes in the circadian clock to alter the expression of target genes with various functions. We are further investigating networks of genes and exons using an empirical Bayes clustering approach and transcription factor motif enrichment analyses, to better understand how SP orchestrates multiple post-mating responses.