Project Details
Projekt
Targeting RNA virus replication by ZAP, TRIM25, and their cofactors
Applicant
Dr. Dorota Kmiec
Subject Area
Virology
Term
from 2019 to 2022
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 428874181
Cellular restriction factors are the first line defence against viral infections. Successfully-spreading pathogens such as Human Immunodeficiency Virus type 1 (HIV-1) and Ebola Virus (EBOV) needed to evolve effective evasion or counteraction strategies against these factors. Interferon-inducible zinc finger antiviral protein (ZAP) has a broad antiviral activity, which relies on directly binding CpG-dinucleotide containing foreign RNAs and their destruction. It has been proposed that this effective and selective activity of ZAP might contribute to the selective pressure mediating the maintenance of low CpG levels in the genomes of many RNA viruses. ZAP does not possess enzymatic activity therefore it relies on multiple co-factors to mediate and regulate its activity. While some of these co-factors have been identified, it is still unclear which members of the RNA degradation machinery are directly responsible for the destruction of bound RNA and how the activity of ZAP is regulated in the context of antiviral responses. One of these co-factors of ZAP is an E3 ubiquitin ligase, tripartite motif protein 25 (TRIM25), which enhances innate immune responses by ubiquitination of RIG-I, a cytosolic sensor of viral infection. Although numerous studies confirmed the important role of TRIM25 in enhancing ZAP’s activity, the nature of their interaction and mechanistic consequences of it are still poorly understood. We would therefore like to clarify the contribution of ZAP and TRIM25 to antiviral immunity and characterise their activity and interactome in the context of two RNA viruses with different replication strategies, HIV-1 and EBOV. Comprehensive structure-function-localisation analysis of both proteins will be performed to characterise determinants of their antiviral activity and clarify the underlying molecular mechanism. Furthermore, complementary mass spectrometry-based approaches, tandem affinity purification and BioID2 proximity screening, will enable the identification of important cofactors and regulators of ZAP and TRIM25. These studies performed in the context of IFN stimulation as well as viral infection will fill the gaps in our understanding of how foreign RNAs are targeted to protect the host from dangerous pathogens. This cutting-edge screening is also likely to lead to the identification of novel players in the innate immunity and will provide important clues for future studies looking into potential applications of this CpG-targeting protein in the field of molecular biology or medicine. Despite extensive efforts, RNA viruses remain one of the major concerns for healthcare worldwide. Natural processes that have the ability to target these pathogens are a major source of inspiration for new therapies that could decrease the burden and limit the spread of HIV-1 and EBOV. Therefore, studies improving our understanding of these natural antiviral mechanisms are of major importance for future efforts in fighting deadly infectious diseases.
DFG Programme
Research Fellowships
International Connection
United Kingdom
