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Generation and Assembly of Virus-Specific Nucleocapsids of the Respiratory Syncytial Virus
Published on: July 27, 2021
Nonstructural proteins NS2-3 and NS4A of classical swine fever virus: essential features for infectious particle
Hervé R Moulin1, Torsten Seuberlich, Oliver Bauhofer
1Institute of Virology and Immunoprophylaxis, Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland. herve.moulin@ivi.admin.ch
Abstract:
The nonstructural protein NS2-3 of pestiviruses undergoes tightly regulated processing. For bovine viral diarrhea virus it was shown that uncleaved NS2-3 is required for infectious particle formation while cleaved NS3 is essential for genome replication. To further investigate the functions of NS2-3 and NS4A in the pestivirus life cycle, we established T7 RNA polymerase-dependent trans-complementation for p7-NS2-3-4A of classical swine fever virus (CSFV). Expression of NS2-3 and NS4A in trans restored the production of infectious particles from genomes lacking NS2-3 expression. Co-expression of cleaved NS4A was essential. None of the enzymatic activities harbored by NS2-3 were required for infectious particle formation. Importantly, expression of uncleavable NS2-3 together with NS4A rescued infectious particles from a genome lacking NS2, demonstrating that cleaved NS2 per se has no additional essential function. These data indicate that NS2-3 and NS3, each in association with NS4A, have independent functions in the CSFV life cycle.
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