Mutational atlas of dengue virus non-structural protein 1 (NS1) in cell culture and mosquitos: mapping infection at single-cell resolution

Dengue virus (DENV) is the most prevalent arbovirus worldwide and its ability to rapidly evolve and adapt complicates efforts to control its spread. A key factor in the replication cycle of DENV is the multifunctional non-structural protein 1 (NS1), which is involved in viral replication, transmission, and pathogenesis. Despite its importance, the evolutionary constraints and host-specific functions of NS1 remain poorly understood. To address this gap, I propose MOSAIC: a comprehensive approach to map the impact of NS1 variants on DENV infection. Using deep mutational scanning (DMS), I will generate diverse viral populations to assess the fitness effects of DENV NS1 variants in mosquito and human cell lines, uncovering host-specific selective pressures. These diverse populations will then be used for in vivo mosquito infection to generate a detailed atlas of NS1 variant distribution across mosquito cells and map the corresponding mosquito transcriptome at single-cell resolution. By combining my expertise in virus evolution with the leading work of the host lab on insect immunity, MOSAIC will uniquely integrate DMS and single-cell transcriptomics, establishing the foundation for novel ways to understand virus evolution at high resolution. MOSAIC will reveal insights into the evolutionary constraints of DENV NS1, identify transmission bottlenecks in distinct mosquito organs and cell types, and explore the interaction between DENV and mosquito immunity. This work will advance our understanding of flavivirus biology and host-virus interactions from a novel perspective, informing the development of new vector control strategies, vaccines, and therapeutics to combat DENV and other arboviral diseases in line with EU global health priorities. Finally, MOSAIC will provide me with multidisciplinary training in advanced genomics, vector biology and bioinformatics, strengthening my expertise in infectious disease research and preparing me to become an independent researcher.