Reproductive functions and genetic architecture of the seminal fluid and sperm proteomes of the mosquitoAedes aegypti

Abstract

The yellow fever mosquito, Aedes aegypti, transmits several viruses, including dengue, Zika, and chikungunya. Some proposed efforts to control this vector involve manipulating reproduction to suppress wild populations or replacing them with disease-resistant mosquitoes. The design of such strategies requires an intimate knowledge of reproductive processes, yet our basic understanding of reproductive genetics in this vector remains largely incomplete. To accelerate future investigations, we have comprehensively catalogued sperm and seminal fluid proteins (SFPs) transferred to females in the ejaculate using tandem mass spectrometry. By excluding female-derived proteins using an isotopic labelling approach, we identified 870 sperm proteins and 280 seminal fluid proteins. Functional composition analysis revealed parallels with known aspects of sperm biology and SFP function in other insects. To corroborate our proteome characterization, we also generated transcriptomes for testes and the male accessory glands-the primary contributors to Ae. aegypti sperm and seminal fluid, respectively. Differential gene expression of accessory glands from virgin and mated males suggests that protein translation is upregulated post-mating. Several SFP transcripts were also modulated after mating, but >90% remained unchanged. Finally, a significant enrichment of SFPs was observed on chromosome 1, which harbors the male sex determining locus in this species. Our study provides a comprehensive proteomic and transcriptomic characterization of ejaculate production and composition and thus provides a foundation for future investigations of Ae. aegypti reproductive biology, from functional analysis of individual proteins to broader examination of reproductive processes.

Prospects in Connecting Genetic Variation to Variation in Fertility in Male Bees

“…To further understand the molecular mechanisms of this aerobic metabolism, Drosophila provide a useful model. Drosophila proteomic analysis found sperm proteins are involved with metabolic and respiratory pathways, and these proteins are conserved across insect species [85][86][87][88]. These metabolic pathways are enriched with metabolic processes, including carbon metabolism (e.g., pyruvate and butyrate metabolism, the TCA cycle, and oxidative phosphorylation), and the metabolism of several classes of amino acids [88].…”

“…Drosophila proteomic analysis found sperm proteins are involved with metabolic and respiratory pathways, and these proteins are conserved across insect species [85][86][87][88]. These metabolic pathways are enriched with metabolic processes, including carbon metabolism (e.g., pyruvate and butyrate metabolism, the TCA cycle, and oxidative phosphorylation), and the metabolism of several classes of amino acids [88]. The most transcriptionally abundant proteins in Drosophila testis and sperm are Sperm-Leucylaminopeptidase, S-Lap1 and loopin [86,87,89], which are structural components of mitochondrial paracrystalline material.…”

Mariana Wolfner: 2018 Genetics Society of America Medal

“…These discoveries have also captured the attention of those who see the potential for practical applications. Wolfner's group is now collaborating with Laura Harrington's group, also based at Cornell, to find seminal proteins in the mosquitoes that transmit the Zika and dengue viruses (Degner et al 2018). Better understanding the reproductive biology of disease vectors could one day open up options for controlling the spread of such global diseases.…”