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CpG methylated minichromosomes become inaccessible for V(D)J recombination after undergoing replication
1Department of Pathology, Stanford University School of Medicine, CA 94305-5324.
The EMBO Journal
|January 1, 1992
Summary
CpG methylation significantly hinders V(D)J recombination by creating a resistant chromatin structure after DNA replication. This epigenetic modification impacts antigen receptor accessibility and chromatin assembly during replication.
Area of Science:
- Epigenetics
- Molecular Biology
- Genetics
Background:
- The physical factors governing antigen receptor gene accessibility for V(D)J recombination remain unclear.
- CpG methylation is a key epigenetic modification, but its role in regulating V(D)J recombination accessibility is not well understood.
Purpose of the Study:
- To investigate the influence of CpG methylation on the accessibility of V(D)J recombination sites.
- To elucidate the physical parameters that control V(D)J recombination site accessibility.
Main Methods:
- Utilized minichromosome substrates to model antigen receptor loci.
- Assessed V(D)J recombination efficiency in methylated and unmethylated substrates.
- Measured DNA accessibility using endonuclease digestion assays.
- Examined the role of DNA replication in establishing methylation-dependent chromatin structures.
Main Results:
- CpG methylation reduced V(D)J recombination efficiency by over 100-fold.
- Methylated minichromosome DNA exhibited significantly increased resistance to endonuclease digestion.
- This resistance to recombination and digestion was observed only after DNA replication.
Conclusions:
- CpG methylation induces a chromatin structure that becomes resistant to V(D)J recombination and site-specific cleavage post-replication.
- These findings highlight the role of DNA methylation in controlling V(D)J recombination and influencing chromatin assembly during DNA replication.
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