Viruses: Membranes in Disguise – Editorial on the special issue reporting on the priority program 1175 of the Deutsche Forschungsgemeinschaft (German Research Foundation): ‘Dynamics of cellular membranes and their exploitation by viruses’
Viruses rely on the host they infect for replication and production of infectious progeny. Thus, without exception membrane acquisition of enveloped viruses occurs from cellular membranes. Because of their strict dependence on cells, viruses are used as tools to study cellular processes, providing the distinct advantage that rare cellular events may be highlighted and synchronized during infection. On the other hand, much may be learned about viruses and how to control them by defining cellular processes that are subverted for the specific needs of a virus.
Within the frame of the Germany-wide priority program 1175 ‘dynamics of cellular membranes and their exploitation by viruses’ virologists, cell biologists, biochemists, biophysicists, and structural biologists joined forces to unravel fundamental principles and molecular mechanisms of membrane budding. The central aim was to study the similarities and differences in the envelopment of viruses and cellular membrane dynamics. For this, the network aimed to apply novel and sophisticated technologies to study cellular and viral membranes.
The priority program commenced in 2006 and extended until 2012 with funding by the ‘Deutsche Forschungsgemeinschaft’ (DFG; German Research Foundation). It comprised about twenty different groups, supplying them with a researcher at the pre- or post-doctorial level and some bench-fee. Additional funds were available for annual meetings, providing platforms for exchange of ideas that included a scientific symposium (in 2010) with invited international speakers. With the network finishing in 2012 we decided to summarize its main achievements in a special issue rather than writing a report that would probably have ended up as a file on a computer or as paper copy in a drawer.
The viruses and technologies
The groups within this network came from all over Germany and two from collaborating institutes in the UK (Grünewald, Oxford) and France (Weissenhorn, Grenoble). Most groups studied important human pathogens including herpesviruses (Grünewald, Sodeik (Hanover)), Koszinowski (Munich), Mertens/Walther (Ulm), Mettenleiter (Riems), retroviruses (Briggs (Heidelberg), Grünewald, Kräusslich (Heidelberg), Lindemann (Dresden), Schubert (Erlangen), Weissenhorn), influenza virus (Briggs, Herrmann/Veit (Berlin)), measles virus (Schneider-Schaulies (Würzburg)), vaccinia virus (Krijnse-Locker (Heidelberg)), rabies virus (Conzelmann/Finke (Munich)) and two pathogens classified in safety level 4 (Marburg virus, Becker (Marburg), Briggs) and Lassa virus (Garten, Marburg). A strong emphasis was on electron microscopy techniques for structural analysis of virally modified membranes (Briggs, Grünewald, Krijnse-Locker, Walther Weissenhorn). Another important technology input came from fluorescence methods including ultra-sensitive fluorescence microscopy (Bräuchle/Lamb, Munich) and fluorescence spectroscopy and fluorescence resonance energy transfer (Herrmann/Veit, Schwille (Dresden)) to study interactions between membranes and (viral) proteins. The group of Brügger/Wieland (Heidelberg) contributed high-resolution quantitative mass spectrometry analysis of membrane lipid composition, while the Schwille group provided expertise on artificial membranes including giant unilamellar vesicles. The network was complemented by groups studying cell biology questions e.g., the assembly of nuclear pores (Ellenberg, Heidelberg) and of lipid rafts (Simons, Dresden), providing expertise that could be applied to study viral envelopment.
Overall the networking effect was quite amazing; it enabled virology groups to branch out to technologies not available in their institute and to answer questions that would not have been addressed without the network. A good example for an enabling group was that of Brügger/Wieland, and their expertise in lipid mass spectrometry led them to collaborate with a large number of network members. The success of this collaborative network is also visible in several joint reports in this issue and the many joint publications by groups of the priority program. The network also enabled students and post-docs to travel to other labs to learn and apply new techniques. This resulted in a remarkable and unique networking between students and post-doctoral fellows, independent of their group leaders. On an average year of the network it yielded about 25-30 peer-reviewed publications and there were about 50 joint publications over the entire funding period exemplifying its success. Overall, the network highlighted the strength of virology, biophysics and imaging in Germany and showed that networking these disciplines can have a tremendous output in science.