Project

Discipline

viral RNA synthesis; innate immunity; type I interferon; RNA decay; reverse genetics; viral RNA sensing; RNA virus; Coronavirus; virus replication complex

Lead
Coronaviren sind RNA Viren die schon sehr lange bekannt dafür sind in Nutz- und Haustieren zu schwere Erkrankungen zu führen. Im Menschen konnte man erst durch das Auftreten von zoologischen Viren, z.B. dem SARS-Coroanvirus und dem MERS-Coronavirus, schwere Erkrankungen beobachten. Eine wichtige Voraussetzung zur Etablierung einer robusten Virusvermehrung bei Coronaviren ist deren Eigenschaft frühen antivitalen Wirtsantworten zu entkommen.
Lay summary
Wir gehen davon aus, dass Coronaviren Mechanismen entwickelt haben die den Ort der Genom-Vermehrung, den sogenannten Replikationskomplex, schützen. Dieser Komplex befindet sich an zellulären Membranen in Zytoplasma von infizierten Zellen. In unserem Projekt wollen wir wichtige Virus-Wirt-Interaktionen identifizieren die direkt am Replikationskomplex stattfinden. Wir sind dabei besonders daran interessiert Wirts-Proteine zu finden die entweder von Coronaviren zur Genom-Vermehrung benutzt werden, oder die die coronavirale Genom-Vermehrung hemmen können. Wir denken dass ähnliche Mechanismen bei anderen Viren eine Rolle spielen und unsere Ergebnisse über Coronaviren hinaus von Bedeutung sein können. Die Erforschung dieser Mechanismen wird zudem auch die Entwicklung von neuen Strategien zur Bekämpfung von coronaviralen Infektion ermöglichen.

Direct link to Lay Summary

Last update: 12.07.2017

Lead
Coronaviruses (CoVs) are RNA viruses that have long been known to cause severe disease in livestock and companion animals. In humans, severe and fatal respiratory diseases have beenobserved through the emergence of zoonotic CoVs, such as SARS-CoV and MERS-CoV. There’saccumulating evidence that early events during CoV infection are decisive for disease severity and outcome.
Lay summary
We hypothesize that CoVs have evolved mechanisms to protect their site of RNA replication in the host cell cytoplasm. This site is characterized by the coronaviral replicase complex that is associated with cytoplasmic host cell membranes. In this project we aim to identify critical virus-host interactions that take place at, or near, the viral replicase complex. Specifically, we are interested to identify host cell proteins that either promote or inhibit virus replication. We expect that similar virus-host interactions take place during infection with other RNA viruses. Our anticipated results will therefore have impact beyond coronaviruses and will be instructive to develop novel strategies to combat RNA virus infections.

Direct link to Lay Summary

Last update: 12.07.2017

Active participation

Communication	Title	Media	Place	Year

Number	Title	Start	Funding scheme

"Host innate immune responses to viral RNA"Background: Coronaviruses (CoVs) are RNA viruses that have long been known to cause severe disease in livestock and companion animals. In humans, severe and fatal respiratory diseases have been observed through the emergence of zoonotic CoVs, such as SARS-CoV and MERS-CoV. CoVs are well known to efficiently evade early innate immune responses and enzymatic functions within - and virus-host interactions at - the CoV replication/transcription complex (RTC) are key to efficiently evade early innate immune responses. Working hypothesis and aims: We hypothesize that induction of early innate immune responses to CoV heavily rely on the ability of host cell innate immune sensors to access and recognize viral RNA and that CoVs have evolved efficacious mechanisms to prevent early detection of viral RNA. We further hypothesize that these early virus-host interactions predominantly take place at the CoV RTC. In order to mechanistically understand these innate immune evasion strategies, we will “illuminate” the cellular environment of the CoV RTC to identify host cell factors that are required for CoV replication, and host cell factors that are targeting the CoV RTC to restrict CoV replication. The reverse genetic systems for the mouse hepatitis virus (MHV) and human coronavirus 229E (HCoV-229E) and well characterized recombinant mutant viruses will be used in combination with murine and human models of infection to dissect key steps and key molecules involved in early innate immune responses on the molecular level. We will furthermore employ state-of-the-art technologies involving biotin ligase-mediated proximity labeling and proteomics, CRISPR/Cas9-based functional screens, and transcriptomics in combination with ribosomal profiling to obtain a detailed mechanistic view on (i) key interactions involved in early innate immune responses, (ii) the kinetics of these interactions and (iii) the kinetics of the global host cell response under well-defined conditions. These studies will provide spatial and temporal view of basic principles of viral RNA recognition and antiviral innate immune mechanisms in different primary cell types following virus infection. Expected significance: Our proposed studies will reveal basic principles of viral RNA sensing and antiviral innate immune effector mechanisms that are highly relevant also beyond CoV infections. We expect to identify key molecules, mechanisms and pathways that promote or restrict viral replication at the site of viral RNA synthesis. This information will further our understanding on fundamental aspects of viral RNA synthesis and innate immune responses to RNA virus infection, and will facilitate the development of novel strategies to interfere with viral RNA replication during the early phase of infections.