| Summary: | 碩士 === 國立臺灣大學 === 微生物學研究所 === 106 === Mosquitoes are one of the fatal animals in the world and they act as vectors for several diseases, including malaria, dengue fever, West Nile fever, chikungunya and Zika. Among these diseases, dengue fever is currently one of the world’s most important tropical diseases. More than 50 thousand cases were reported in 2014 and 2015 in Taiwan. However, there is no effective dengue vaccine or drug available so far. Hence, vector control becomes an alternative strategy for dengue control. Dengue virus (DENV) is transmitted to humans by the mosquito Aedes aegypti during the blood meal. In the meantime, DENV and saliva proteins are inoculated into human skin. Previous studies have indicated that proteins from mosquito salivary gland may influence the DENV infectivity in the mammalian host. However, the exact mechanisms of saliva-mediated infectivity enhancement remain unknown largely. It is worth noting that not all the proteins in the salivary gland were secreted. Therefore, the aim of this study is to investigate the role of mosquito saliva on dengue virus infectivity in Aedes aegypti. Our results showed that mosquito saliva proteins are associated with dengue virus proteins in Aedes aegypti via glycan-protein interactions, and these interactions are crucial for dengue virus infectivity. Furthermore, we identified a saliva protein named calreticulin (CRT) to be interacted with dengue prM protein in the mosquito saliva. We found that CRT not only expressed in mosquito saliva but also other tissues. We also demonstrated that CRT is essential for DENV replication in Aedes aegypti. Furthurmore, silencing of CRT resulted in significant reduction of dengue virus infectivity in the mosquito saliva, indicating that CRT plays an important role in DENV transmission. Understanding the role of saliva proteins in DENV transmission will provide novel approaches for the development of new tools for the control of arbovirus-borne diseases transmitted by the same vector.
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