Influence of the host cell on proteins synthesized by different strains of influenza virus

Protein fingerprinting: a novel virus identification system

Viral proteins separated by one-dimensional SDS-PAGE produce protein binding patterns (fingerprints) which are unique for different viruses. We have applied this concept successfully for the development of a practical and objective virus identification system which is applicable to most viruses. The method is simple, specific, and, unlike the currently available methods, free from all virus-specific reagents. Interference by host protein bands in SDS-PAGE preparations of virus-infected cell lysates was eliminated consistently by treating virus infected cell cultures with optimum concentration of NaCl for selective inhibition of host protein synthesis. The method utilizes the comparison of protein fingerprints of 'unknown' viruses with protein fingerprints of reference viruses stored in a computer data base, using pattern recognition software. All 113 'unknown' virus strains were correctly identified to the genus level by the protein fingerprint method, when compared with the conventional virus identification methods.

Regulation of protein synthesis in virus-infected animal cells

This chapter summarizes the structural features that govern the translation of viral mRNAs: where the synthesis of a protein starts and ends, how many proteins can be produced from one mRNA, and how efficiently. It focuses on the interplay between viral and cellular mRNAs and the translational machinery. That interplay, together with the intrinsic structure of viral mRNAs, determines the patterns of translation in infected cells. It also points out some possibilities for translational regulation that can only be glimpsed at present, but are likely to come into focus in the future. The mechanism of selecting the initiation site for protein synthesis appears to follow a single formula. The translational machinery displays a certain flexibility that is exploited more frequently by viral than by cellular mRNAs. Although some of the parameters that determine efficiency have been identified, how efficiently a given mRNA will be translated cannot be predicted by summing the known parameters.

Complementation with an avian influenza virus is required for synthesis of M protein of a human strain in chicken erythocytes

The M protein of avian, but not human, strains of influenza A viruses is synthesized in infected chicken erythrocytes. In dual infections an avian strain complemented the human virus and both the human and avian M proteins were expressed.