RIG‐I Live Imaging · Imaging influenza nucleic acid recognition by RIG-I in living cells
FP7 — People (Marie Curie Actions)
- Duration
- 2011-05-01 → 2013-04-30
- EU contribution
- €200,050
- Participants
- 1
- Scheme
- MC-IEF
Lines connect the coordinator with its partners.
Results in brief
Imaging influenza nucleic acid recognition by RIG-I in living cells.
Among all pathogens, RNA viruses impose a particular challenge due to their ability to evolve rapidly. As intracellular parasites, they directly interact with the host cell machinery and can develop diverse resistance mechanisms to bypass cellular defenses. Hence, it is of crucial importance for the host to react at early steps of the infection. During infection, viral nucleic acids can be sensed by members of the RIG-I like receptors family, namely RIG-I, MDA5 and LGP2. These receptors trigger a rapid response that acts to limit virus replication. Recently much progress has been made in defining the features of RNA recognized by RIG-I and the project therefore re-focused on the fact that much less information is available on the characteristics of RNA recognized by MDA5 or LGP2. The proposal was therefore redesigned to focus on defining the physiological agonists for MDA5 that promote signalling in infected cells. To do this, we focused on the encephalomyocarditis virus (EMCV) infection model, which is a member of the picornaviridae family such as Polio, Rhino, or Coxsackie viruses. We purify RNA directly from complexes obtained by immunoprecipitation of the MDA5 partner, LGP2 and show that this method enriches for stimulatory RNA corresponding to a short portion of the EMCV antisense RNA. Deletion of this region from the EMCV genome generates viruses that are less potent at producing stimulatory RNA and inducing IFN in infected cells or mice. Thus, a discrete region of the EMCV antisense genome can act as a physiologically-relevant MDA5 agonist in infected cells. Identification of the RNAs responsible for MDA5 activation in infected cells sheds light into the nature of RLR recognition and may help develop new ways to prevent and control picornavirus spread. In sum, the results from the project contribute to a better understanding of the innate antiviral response and, potentially, impact on antiviral treatments and vaccine development.
Data: CORDIS, © European Union
Project objective
Despite of intensive research the last decades, viral infection still represents a serious threat to human health. One crucial aspect of the defence against viral infection is the activation of the host innate immune response. Recent advances have highlighted the crucial role of the RIG-I receptor in triggering IFN synthesis upon virus infections. This virus sensing pathway mediated by RIG-I is crucial for successful host defence against negative stranded RNA viruses infection such as influenza virus. Influenza viruses are common pathogens responsible for recurrent seasonal respiratory illness and pose a serious threat to public health. Part of the virulence of influenza virus is due to its ability to manipulate the innate immune system. Therefore it is important to understand the mechanism of influenza detection by the RIG-I receptor. Much work in the host and other laboratories has contributed to our understanding of how influenza infection initiates the activation of RIG-I and the identity and properties of RIG-I agonists are well defined. However, the kinetics, subcellular localization and mechanisms underlying this recognition still remain unclear. This question of the localisation of virus recognition and the accessibility of the RIG-I ligand is stressed by the subcellular site of virus replication. For example, the replication cycle of influenza virus occurred in the nucleus of infected cells. Therefore it is quite puzzling how RIG-I that has been described to be a cytoplasmic receptor could be able to interact with the viral genome. The overall goal of this project is to develop a non-invasive technique that allows visualization and localization of influenza nucleic acid replication to analyze its detection by the RIG-I innate immune receptor in living cells. Documenting the spatiotemporal detection of influenza genome will certainly improve our understanding of the host-defence race.
Original text from CORDIS.
Participants
- CANCER RESEARCH UK LBG · LONDONCoordinatorUnited Kingdom
Links
Data: CORDIS, © European Union