Effect of receipt of male ejaculate sex peptide on micro RNA expression in female Drosophila melanogaster, 3 hours after the start of mating, in HeadThorax (HT) and Abdomen (Abd) tissues.. Drosophila melanogaster

Seminal fluid proteins (Sfps) can have significant effects on female behaviour and physiology. In Drosophila melanogaster a single Sfp, sex peptide (SP), triggers a remarkably diverse array of fundamentally important responses. It increases female fecundity, juvenile hormone (JH) production, antimicrobial peptide production and feeding rates, whilst decreasing sexual receptivity. Although these features are expected to leave a strong genomic signature, previous studies indicated that Sfps affect the expression of relatively modest numbers of genes. A potential explanation is that increased resolution is needed or that SP could also elicit post-transcriptional control at the level of microRNAs (miRs). We hypothesised that responses to SP at both the transcriptional and post-transcriptional levels could provide precise temporal and spatial responsiveness and facilitate the expression of diverse phenotypes from a single ligand. To test this idea, we used microarrays and Solexa deep sequencing to profile mRNA and miR responses to SP in adult female abdomen (Abd) and head+thorax (HT) tissues. SP elicited a rich but subtle signature of temporally and spatially controlled mRNAs related to functions that match the predicted known effects of SP, but that also suggest potentially novel roles for SP such as in phototransduction. mRNA profiles were much more varied in the HT than in the Abd, both within and across time points (3 and 6h after mating). The deep sequencing data revealed post-transcriptional control of SP responses by differential expression of miRs in adults. As for the mRNA profiles, there was evidence for tissue specificity. miRs showing largest expression differences tended to be down regulated in the HT and up regulated in the Abd. Receipt of SP significantly down-regulated the expression of miR279, a micro-RNA with potentially diverse sensory and reproductive roles, across the HT and Abd. We also identified potential differential expression for miRs 31A, 184, 276A and 989. Our study provides the first evidence of changes in both transcriptional and post-transcriptional expression in adults in response to Sfps, and provides a potential mechanism for the extraordinary diversity of responses seen in response to the single SP stimulus. Overall design: Examination of microRNA expression level changes in HeadThorax and Abdomen tissues of females 3 hours after receipt of a full ejaculate (SP+) versus an ejaculate minus sex peptide (SP0). 2 biological replicates of each treatment (replicates 3 and 4 for HT and 2 and 4 for Abd). This submission represents the Solexa deep sequencing component of the study.