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Identification of critical elements within the JC virus DNA replication origin
1Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802.
Journal of Virology
|December 1, 1990
Summary
The JC virus (JCV) T antigen shows limited interaction with replication origins, unlike the SV40 T antigen. Specific sequences in the JCV origin, particularly the A+T-rich tract, dictate replication efficiency.
Area of Science:
- Molecular Virology
- Viral Replication Mechanisms
- Polyomavirus Biology
Background:
- JC virus (JCV) and Simian Virus 40 (SV40) are polyomaviruses with distinct T antigens and replication origins.
- T antigens are crucial viral proteins that initiate viral DNA replication.
- Understanding the specificity of T antigen-origin interactions is key to viral replication.
Purpose of the Study:
- To investigate the basis for the restricted interaction between JCV T antigen and the SV40 origin of replication.
- To identify the specific elements within the JCV replication origin that mediate productive replication.
- To determine the role of different T antigens in driving replication from homologous and heterologous origins.
Main Methods:
- Analysis of the JCV replication origin structure.
- Construction and testing of JCV-SV40 hybrid origin plasmids.
- Replication assays in cells expressing either JCV or SV40 T antigen.
- Site-directed mutagenesis of the JCV origin.
Main Results:
- JCV T antigen does not efficiently replicate from the SV40 origin, while SV40 T antigen replicates from both JCV and SV40 origins.
- A specific region on the late side of the JCV origin's central palindrome is critical for JCV T antigen interaction.
- The A+T-rich tract within the JCV origin is a primary determinant of replication efficiency mediated by JCV T antigen.
- The AGGGA repeat sequence in the JCV enhancer stimulates JCV T antigen-driven replication but not SV40 T antigen-driven replication.
- JCV T antigen cannot efficiently replicate a BK virus origin, highlighting its origin-interaction inflexibility.
Conclusions:
- The JCV T antigen exhibits strict specificity for its cognate replication origin.
- The A+T-rich tract and enhancer elements within the JCV origin play distinct roles in mediating replication dependent on the specific T antigen.
- These findings elucidate the molecular basis for species-specific replication of polyomaviruses.