Reverse genetic characterization of the natural genomic deletion in SARS-Coronavirus strain Frankfurt-1 open reading frame 7b reveals an attenuating function of the 7b protein in-vitro and in-vivo | Virology Journal BioMed Central Research Reverse genetic characterization of the natural genomic deletion in SARS-Coronavirus strain Frankfurt-1 open reading frame 7b reveals an attenuating function of the 7b protein in-vitro and in-vivo Susanne Pfefferle 1 Verena Krahling2 Vanessa Ditt3 Klaus Grywna1 Elke Muhlberger2 4 5 and Christian Drosten 1 3 Open Access Address 1Clinical Virology Group Bernhard Nocht Institute for Tropical Medicine Hamburg Germany 2Department of Virology Philipps University Marburg Germany institute of Virology University of Bonn Medical Centre Bonn Germany 4National Infectious Diseases Laboratories Institute Boston USA and 5Department of Microbiology Boston University School of Medicine Boston USA Email Susanne Pfefferle - pfefferle@ Verena Krahling - kraehliv@ Vanessa Ditt - ditt@ Klaus Grywna - grywna@ Elke Muhlberger - muehlber@ Christian Drosten - drosten@ Corresponding author Published 24 August 2009 Received 30 July 2009 Accepted 24 August 2009 Virology Journal 2009 6 131 doi 1743-422X-6-13 1 This article is available from http content 6 1 131 2009 Pfefferle et al licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract During the outbreak of SARS in 2002 3 a prototype virus was isolated from a patient in Frankfurt Germany strain Frankfurt-1 . As opposed to all other SARS-Coronavirus strains Frankfurt-1 has a 45-nucleotide deletion in the transmembrane domain of its ORF 7b protein. When overexpressed in HEK 293 cells the full-length protein but not the variant with the deletion caused interferon beta induction and cleavage of procaspase 3. To study the role of ORF 7b in the context
