Identification of mosquito proteins that differentially interact with alphavirus nonstructural protein 3, a determinant of vector specificity.

Chikungunya virus (CHIKV) and the closely related onyong-nyong virus (ONNV) are arthritogenic arboviruses that have caused significant, often debilitating, disease in millions of people. However, despite their kinship, they are vectored by different mosquito subfamilies that diverged 180 million years ago (anopheline versus culicine subfamilies). Previous work indicated that the nonstructural protein 3 (nsP3) of these alphaviruses was partially responsible for this vector specificity. To better understand the cellular components controlling alphavirus vector specificity, a cell culture model system of the anopheline restriction of CHIKV was developed along with a protein expression strategy. Mosquito proteins that differentially interacted with CHIKV nsP3 or ONNV nsP3 were identified. Six proteins were identified that specifically bound ONNV nsP3, ten that bound CHIKV nsP3 and eight that interacted with both. In addition to identifying novel factors that may play a role in virus/vector processing, these lists included host proteins that have been previously implicated as contributing to alphavirus replication. Author summary: Alphaviruses such as CHIKV and ONNV, cause severely painful human illnesses and are capable of producing large outbreaks with endemic persistence. Half of the alphavirus lifecycle is in mosquitoes, making it important to understand the molecular interactions between the virus and the vector that influence the capacity of these viruses to spread. This work identifies 24 vector proteins that may be responsible for restricting CHIKV from infecting the subfamily of mosquitoes that ONNV, CHIKV's closest relative, uses for transmission. This is the first study to identify Anopheles host proteins that interact with alphavirus nonstructural protein 3. Understanding these virus/vector interactions is important for identifying risk factors for viral transmission and potential mechanisms for controlling vector infections by human pathogens. [ABSTRACT FROM AUTHOR]