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EBNA1 distorts oriP, the Epstein-Barr virus latent replication origin
1Howard Hughes Medical Institute, Microbiology Department, Cornell University Medical College, New York, New York 10021.
Journal of Virology
|March 1, 1992
Summary
Epstein-Barr virus nuclear antigen 1 (EBNA1) binding to oriP induces a helical distortion, making specific thymines reactive. This distortion, occurring on the opposite face of the DNA helix from EBNA1 binding, may be key to initiating viral replication.
Area of Science:
- Virology
- Molecular Biology
- Epigenetics
Background:
- Epstein-Barr virus nuclear antigen 1 (EBNA1) is essential for viral DNA replication.
- EBNA1 binds to the viral latent replication origin (oriP) to facilitate replication initiation.
Purpose of the Study:
- To investigate the molecular mechanism by which EBNA1 activates replication at oriP.
- To identify structural changes in oriP upon EBNA1 binding.
Main Methods:
- Potassium permanganate (KMnO4) reactivity assays to detect DNA helical distortions.
- Dimethyl sulfate (DMS) protection assays to map protein binding sites on the DNA helix.
Main Results:
- KMnO4 treatment revealed two thymine residues, 64 bp apart in the oriP dyad symmetry region, became reactive upon EBNA1 binding.
- DMS protection studies showed EBNA1 binds to the DNA face opposite these reactive thymines, suggesting a specific helical distortion.
Conclusions:
- EBNA1 binding to oriP induces a significant helical distortion.
- This distortion, located opposite the EBNA1 binding site, is proposed to play a role in initiating Epstein-Barr virus replication.