Evolution of a Novel Neuronal Sex-Specifically Spliced Gene in Mosquitoes

<p>Female mosquitoes from many species require a blood meal from an animal host as a protein source for egg development and successful reproduction. The majority of mosquito species are generalists in their host preference, feeding on a range of animals including mammals, birds, and amphibians. However, a small fraction of mosquito species have evolved a preference for human hosts. These species are mainly found in the genera <em>Aedes</em>, <em>Culex</em>, and <em>Anopheles</em>, and they have created a global health crisis due to their ability to transmit deadly human pathogens including dengue virus, Zika virus, West Nile Virus, and the <em>Plasmodium</em> malaria parasite. Understanding the mechanisms that generate these important sexually dimorphic behaviors in mosquitoes is a crucial step towards developing strategies to combat vector borne disease spread. In this work, we investigate the molecular mechanisms of sexually dimorphic behaviors in mosquitoes by characterizing a novel sex-specifically spliced gene called <em>AAEL011211</em>, which was first identified in <em>Aedes aegypti</em> brains and is well conserved in the mosquito lineage. Sex-specific splicing of key genes is a conserved hallmark of genetic regulation of sexual dimorphism in insects. We comprehensively characterize the gene locus and the conserved sex-specific splicing of <em>AAEL011211</em> in representative species from the mosquito lineage. Additionally, we take advantage of available sex-specific bulk RNA sequencing and single nucleus RNA sequencing data across mosquito tissue to characterize the expression pattern of <em>AAEL011211</em> in <em>Aedes aegypti</em>. We find that it is enriched in the nervous system and is neuron-specific, suggesting that it may contribute to sexually dimorphic behaviors in the mosquito. We examine the predicted <em>AEEL011211</em> protein and show that the sex-specific splicing leads to a shorter protein in the female and a longer protein in the male. Homology and phylogenetic analyses show that <em>AAEL011211</em> proteins have close homologs in the mosquito lineage, distant homologs across the insect tree of life, and no evidence of homologs in vertebrate genomes. While the <em>AAEL011211</em> proteins have no homology to functionally characterized domains, they are predicted to be nuclear proteins both in mosquitoes and in the distant insect homologs. Moreover, we discover a novel ~200 amino acid domain in <em>AAEL011211</em>, with one copy (D1) in the female protein and two copies (D1 and D2) in the male protein following a domain duplication event. While D1 is found in many insect species, D2 is a male-specific duplication unique to the mosquito lineage, revealing a mosquito-specific sexual dimorphism at the protein level for <em>AAEL011211</em>. The function of <em>AAEL011211</em>is unknown, and future work will be needed to study what role it plays in the unique sexually dimorphic behaviors of mosquitoes. Our characterization of <em>AAEL011211</em> as a novel conserved mosquito sex-specifically spliced gene expands our knowledge of the potential molecular mechanisms that underlie sexual dimorphism in mosquitoes. Until now, <em>fruitless</em> and <em>doublesex</em> were the only described sex-specifically spliced genes, highlighting the rarity and importance of such regulation. In particular, the neuronal specificity and sex-specific protein domain features of <em>AAEL011211</em> in mosquitoes suggest that it may function in regulating key female-specific behaviors like host seeking and blood feeding that are central to disease transmission. Future work to understand <em>AAEL011211</em> may inform and expand the options for vector control strategies aimed at disrupting female-specific behaviors that are critical for pathogen spread.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Thesis

Year

2026

Author dc:creator

• Tsitohay, Yael Norohasimbola

Contributors dc:contributor

• Leslie B. Vosshall

• Aedes aegypti
• mosquito
• sex-specific RNA splicing
• protein evolution
• insects
• Life Sciences

Repository record dc:identifier

https://digitalcommons.rockefeller.edu/student_theses_and_dissertations/847

OAI identifier oai:identifier

oai:digitalcommons.rockefeller.edu:student_theses_and_dissertations-1851