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Characterization of the gene encoding the A-type inclusion body protein of mousepox virus
N Osterrieder1, H Meyer, M Pfeffer
1Institute of Medical Microbiology, Infectious and Epidemic Diseases, Ludwig-Maximilians-Universität Munich, FRG.
Abstract:
The gene of the mousepox virus strain MP-1 coding for the protein of A-type inclusions was identified and sequenced. The gene maps in the HindIII-A fragment at the same position as the cowpox-virus Brighton 160 kD gene (1) and the closely related 94 kD LS gene of vaccinia virus strain Western Reserve (2,3). The encoded protein consists of 1049 amino acids with a predicted molecular weight of 122.5 kD, which corresponds well to the apparent molecular weight of 130 kD estimated after polyacrylamide gel electrophoresis and Western blotting. The protein is a characteristic feature of mousepox virus and could be demonstrated for five independently isolated strains. The MP-1 ATI protein displays a similarity of 82.3% to the cowpox virus Brighton 160 kD protein, the first 340 amino acids being almost identical. However, two major deletions of 55 and 92 amino acids were observed from amino acid positions 671 to 732 and 794 to 885, respectively. Furthermore, the C-terminal residues (position 998-1049 of the MP-1 sequence) did not match at satisfactory levels with cowpox nor with vaccinia virus sequences. According to Western blot and protein alignment data as well as hydropathy predictions, the 130 and 160 kD proteins closely resemble each other, indicating similar structure and function.
Insights
Researchers identified and sequenced the mousepox virus A-type inclusions protein (ATI). This protein shares significant similarity with cowpox virus ATI, suggesting conserved structure and function in orthopoxviruses.
Area of Science:
- Virology
- Molecular Biology
- Genetics
Background:
- A-type inclusions (ATI) are characteristic protein inclusions found in orthopoxviruses.
- The specific gene and protein responsible for ATI in mousepox virus (MP-1 strain) were not fully characterized.
- Understanding ATI proteins is crucial for differentiating between poxvirus species.
Purpose of the Study:
- To identify and sequence the gene encoding the A-type inclusions (ATI) protein in the mousepox virus MP-1 strain.
- To compare the MP-1 ATI protein with homologous proteins from related poxviruses, specifically cowpox and vaccinia viruses.
- To elucidate the structural and functional similarities and differences of the MP-1 ATI protein.
Main Methods:
- Gene identification and DNA sequencing of the MP-1 strain.
- Bioinformatic analysis including amino acid sequence alignment and hydropathy prediction.
- Protein analysis using polyacrylamide gel electrophoresis and Western blotting.
Main Results:
- The gene for the MP-1 ATI protein was identified and sequenced, mapping to the HindIII-A fragment.
- The encoded protein has 1049 amino acids with a predicted molecular weight of 122.5 kD, consistent with experimental estimates.
- The MP-1 ATI protein shows 82.3% similarity to the cowpox virus Brighton 160 kD protein, with notable deletions and distinct C-terminal residues.
- The protein was found in five independent mousepox virus isolates, confirming it as a characteristic feature.
Conclusions:
- The MP-1 ATI protein is a conserved feature of mousepox virus strains.
- Significant sequence similarity suggests conserved structure and function between mousepox and cowpox virus ATI proteins.
- Observed sequence variations, including deletions, may contribute to species-specific characteristics of orthopoxviruses.