title: In vivo proteins of defective interfering particles of poliovirus.
abstract: DX particles of poliovirus are deletion mutants that do not induce synthesis of capsid proteins or the precursor of capsid proteins (NCVPla) during infection. However, cells infected with DX particles synthesize two proteins, p68 and p25, that are not detected during growth of standard virus, and a protein of 27 000 (p27) which is comparable in molecular weight to VP3. Peptide maps of these proteins were obtained by partial digestion with Staphylococcus aureus V8 protease and elastase. The peptide map of p68 corresponded approximately 70% with the peptide map of NCVPla, and antiserum against virions reacted with p68. These data suggest that p68 is a large fragment of NCVPla. Digestion of purified structural proteins VP1, VP2, and VP3 yielded distinct peptide maps, but p25 was resistant to both V8 protease and elastase and did not react noticeably with anticapsid antibody. Peptide maps obtained for in vivo viral proteins migrating with a molecular weight of 27 000 were complex, indicating the presence of at least two and possibly three proteins. Cells infected with standard gs and gr viruses produced authentic VP3, but cells infected with defective interfering particles did not. However, one gr variant of standard virus contained a mutation in structural protein VP2.
mesh_terms: D002213:Capsid / Q000302:isolation & purification; D003673:Defective Viruses / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D010450:Endopeptidases; D006367:HeLa Cells / Q000032:analysis; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D017955:Poliovirus / Q000032:analysis*; D014764:Viral Proteins / Q000302:isolation & purification*
chemical_list: D010446:Peptide Fragments; D014764:Viral Proteins; D010450:Endopeptidases