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Regulation of mouse satellite DNA replication time
The EMBO Journal
|February 1, 1988
Summary
Satellite DNA replication timing is linked to DNA methylation. Modifying methylation patterns can alter replication timing, suggesting epigenetic control over this process in mouse cells.
Area of Science:
- Epigenetics
- Molecular Biology
- Genomics
Background:
- Satellite DNA near centromeres typically replicates late in S-phase.
- This late replication is associated with heavy CpG methylation in mouse fibroblasts and lymphocytes.
- F9 teratocarcinoma cells exhibit undermethylated satellite DNA that replicates early.
Purpose of the Study:
- To investigate the role of DNA methylation in controlling satellite DNA replication timing.
- To explore potential trans-acting factors involved in regulating replication timing.
Main Methods:
- Analysis of satellite DNA replication timing in different mouse cell types (fibroblasts, lymphocytes, F9 teratocarcinoma cells).
- Treatment with 5-azacytidine to demethylate DNA.
- Cell fusion experiments between F9 cells and mouse lymphocytes.
- Assessment of DNase I sensitivity in relation to replication timing.
Main Results:
- 5-azacytidine treatment shifted late-replicating satellite DNA to mid-S phase.
- Early replication of satellite DNA was not linked to increased DNase I sensitivity.
- Fusion with F9 cells induced an early replication shift in lymphocyte satellite heterochromatin.
Conclusions:
- DNA methylation plays a significant role in regulating satellite DNA replication timing.
- Trans-acting factors may be involved in the epigenetic control of replication timing for heterochromatin.