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Identification of the human papilloma virus-1a E4 gene products
Abstract:
Antibodies prepared against a human papilloma virus-1 (HPV-1) E4/beta-galactosidase fusion protein identified several polypeptides in HPV-1, but not HPV-2 or 4, induced papillomas. The major E4 protein, that represented up to 30% of total cellular protein, was a 16/17-K doublet which was purified by column chromatography and analysed for amino acid content. A peptide derived by chymotryptic digestion was purified by h.p.l.c. and subjected to amino acid sequencing. The unique sequence obtained, Gly-His-Pro-Asp-Leu-Ser-Leu, identified the 16/17-K doublet as a product of the HPV-1 E4 gene region. Antibodies to both the E4/beta-galactosidase fusion protein and the 16/17-K doublet identified two smaller polypeptides (10/11-K) which may represent spliced products of E4. We propose that the products of the HPV-1 E4 gene region are not classical DNA tumor virus early proteins and suggest that they play a role in virus maturation.
Insights
Researchers identified human papilloma virus-1 (HPV-1) E4 proteins, including a major 16/17-K doublet and smaller 10/11-K products, suggesting a role in virus maturation. These findings differentiate HPV-1 E4 proteins from typical DNA tumor virus early proteins.
Area of Science:
- Virology
- Molecular Biology
- Oncology
Background:
- Human papillomaviruses (HPVs) are associated with various cancers.
- The early region 4 (E4) genes of HPVs are crucial for viral replication and pathogenesis.
- Understanding HPV-1 E4 protein function is essential for developing targeted therapies.
Purpose of the Study:
- To characterize the protein products of the HPV-1 E4 gene region.
- To determine the function of HPV-1 E4 proteins in viral pathogenesis.
- To differentiate HPV-1 E4 proteins from other DNA tumor virus early proteins.
Main Methods:
- Generation of antibodies against an HPV-1 E4/beta-galactosidase fusion protein.
- Identification and purification of HPV-1 E4-related polypeptides using column chromatography and HPLC.
- Amino acid analysis and sequencing of purified HPV-1 E4 peptides.
- Western blot analysis using specific antibodies to detect E4 protein products.
Main Results:
- Antibodies identified a major 16/17-K doublet and smaller 10/11-K polypeptides in HPV-1 induced papillomas.
- Amino acid sequencing confirmed the 16/17-K doublet as a product of the HPV-1 E4 gene region.
- The identified E4 proteins were specific to HPV-1 and not found in HPV-2 or HPV-4.
- Smaller polypeptides may represent spliced products of the HPV-1 E4 gene.
Conclusions:
- The HPV-1 E4 gene region produces distinct polypeptides, including a major 16/17-K doublet and potential spliced variants.
- These E4 proteins are not classical DNA tumor virus early proteins.
- HPV-1 E4 proteins likely play a significant role in the maturation of the virus.