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Internal proteins of influenza virus: 35S-methionine peptide maps as genetic markers
Abstract:
Methods are described for the preparation in vivo of 35S-methionine-labelled influenza viruses, the purifiction of the nucleoprotein (NP) and matrix (M) proteins and the separation of peptides obtained by protease digestion by two-dimensional thin-layer chromatography. The maps of the M proteins of A/Okuda/57(H2N2) and A/Finland/4/74(H3N2) were very similar overall but differed in three peptides. Hence they could be clearly distinguished. Maps of the NP proteins of the same strains showed a greater number of differences. A recombinant strain having the haemagglutinin and neuraminidase of the A/Finland/4/74 parent and the virulence of the A/Okuda/57 parent was shown to have the M and P proteins of A/okuda/57.
Insights
This study details a method for analyzing influenza virus proteins, specifically nucleoprotein (NP) and matrix (M) proteins, using protease digestion and chromatography. Differences in these protein maps help distinguish between influenza virus strains.
Area of Science:
- Virology
- Molecular Biology
- Biochemistry
Background:
- Influenza virus characterization is crucial for understanding viral evolution and pathogenesis.
- Distinguishing between influenza virus strains aids in epidemiological surveillance and vaccine development.
Purpose of the Study:
- To develop and apply a method for comparing influenza virus matrix (M) and nucleoprotein (NP) structures.
- To differentiate between influenza A virus strains based on their protein profiles.
Main Methods:
- Preparation of 35S-methionine-labelled influenza viruses in vivo.
- Purification of nucleoprotein (NP) and matrix (M) proteins.
- Protease digestion and peptide separation using two-dimensional thin-layer chromatography.
Main Results:
- Peptide maps of matrix (M) proteins from A/Okuda/57 and A/Finland/4/74 strains showed high similarity with distinct differences in three peptides, allowing clear differentiation.
- Nucleoprotein (NP) protein maps exhibited more significant differences between the same strains.
- A recombinant influenza virus strain inherited the M and P proteins from the virulent A/Okuda/57 parent, despite possessing haemagglutinin and neuraminidase from A/Finland/4/74.
Conclusions:
- Two-dimensional thin-layer chromatography of protease digests provides a sensitive method for distinguishing influenza virus strains.
- The M and NP protein profiles are valuable markers for influenza virus strain identification and characterization.
- Recombinant influenza virus studies indicate that virulence traits can be associated with specific internal proteins like M and P.