|JOHNSON, RICHARD - University Of Washington|
|SWEENEY, MICHELLE - Boyce Thompson Institute|
|KARASEV, ALEXANDER - University Of Idaho|
|MACCOSS, MICHAEL - University Of Washington|
Submitted to: Proteomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2015
Publication Date: 4/29/2015
Citation: Deblasio, S.L., Johnson, R., Sweeney, M., Karasev, A., Gray, S.M., Maccoss, M., Cilia, M. 2015. The Potato leafroll virus structural proteins manipulate overlapping, yet distinct protein interaction networks during infection. Proteomics. 15(12):2098-2112.
Interpretive Summary: Potato leafroll virus (PLRV) infects potatoes and is exclusively transmitted by sap-sucking aphid vectors. The virus encodes a protein shell that is comprised of two structural proteins, the coat protein and the readthrough protein. Like a scaffold, these two structural proteins make a small cage that encloses the virus' genetic material as it moves throughout the plant and aphid vector. Previous work done by others has demonstrated that the two structural proteins orchestrate several major functions of the virus during infection and insect transmission. Mutational analysis of the virus has shown that the coat protein and readthrough protein have some overlapping functions, but also some unique to each protein. For example, the readthrough protein regulates the ability of the virus to remain localized to the vascular tissue, which is important for aphid transmission. Although the precise molecular basis for those shared and specific functions are not known, we hypothesize they are regulated by protein interactions. In this study we applied a new protein interaction mapping technology to compare a fully infectious (called wild type) virus to a mutant virus that lacks the readthrough domain. The mutant virus is still infectious, but is defective in systemic plant movement and aphid transmission. By comparing protein interaction networks between the wild type and mutant virus, we could map the molecular pathways regulated specifically by the readthrough protein. Importantly, the data support the hypothesis that readthrough protein manipulates the plant's photosynthetic machinery during infection. This work shows that by coupling genetic and high throughput approaches, identification of specific protein interaction networks regulated by viral proteins during infection can be identified. These data will be useful to develop novel breeding targets and control methods in potato for resistance to PLRV.
Technical Abstract: Potato leafroll virus (PLRV) produces a readthrough protein (RTP) via translational readthrough of the coat protein amber stop codon. The RTP functions as a structural component of the virion and as a non-incorporated protein in concert with numerous insect and plant proteins to regulate virus movement/transmission and tissue tropism. Affinity purification coupled to quantitative MS was used to generate protein interaction networks for a PLRV mutant that is unable to produce the read through domain (RTD) and compared to the known wild-type PLRV protein interaction network. By quantifying differences in the protein interaction networks, we identified four distinct classes of PLRV-plant interactions: those plant and nonstructural viral proteins interacting with assembled coat protein (category I); plant proteins in complex with both coat protein and RTD (category II); plant proteins in complex with the RTD (category III); and plant proteins that had higher affinity for virions lacking the RTD (category IV). Proteins identified as interacting with the RTD are potential candidates for regulating viral processes that are mediated by the RTP such as phloem retention and systemic movement and can potentially be useful targets for the development of strategies to prevent infection and/or viral transmission of Luteoviridae species that infect important crop species.