Proteins present in bovine papillomavirus particles

Area of Science:

• Virology
• Structural Biology
• Molecular Biology

Background:

• Bovine papillomavirus (BPV) is a significant animal pathogen.
• Understanding the structural proteins of BPV is crucial for developing antiviral strategies.
• The major capsid protein L1 plays a key role in viral particle formation.

Purpose of the Study:

• To investigate the post-translational modifications of the BPV L1 protein.
• To explore the potential role of L1 modifications in particle stability.
• To examine the interaction of L1 with viral DNA.

Main Methods:

• Two-dimensional gel electrophoresis and silver staining were employed to analyze BPV particles.
• Neuraminidase treatment was used to assess the nature of L1 modifications.
• Theoretical mobility calculations were performed to compare protein properties.

Main Results:

• The major capsid protein L1 exhibits extensive modifications, with at least 13 isoelectric point variants.
• A heavier 69 kDa protein chain, likely derived from L1 via glycosylation, was identified.
• Neuraminidase treatment altered L1 modification patterns, suggesting sialic acid involvement.
• Proteins with histone-like molecular masses were detected, potentially encoded by BPV E7 and E5 ORFs.

Conclusions:

• BPV L1 undergoes significant post-translational modifications, including glycosylation, which may contribute to particle stability.
• The basic tails of L1 may interact with viral DNA similarly to histones.
• BPV may encode histone-like proteins through its E7 and E5 open reading frames, offering new insights into viral genome packaging.