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C-myc expression is maintained during the G1 phase cell cycle block produced by beryllium
D N Skilleter1, N C Barrass, R J Price
1MRC Toxicology Unit, BIBRA, Carshalton, Surrey, UK.
Cell Proliferation
|March 1, 1991
Summary
Beryllium salts inhibit cell division but surprisingly maintain expression of the c-myc proto-oncogene in BL9L cells. This suggests beryllium modulates gene transcription rather than blocking it entirely.
Area of Science:
- Cell Biology
- Toxicology
- Molecular Biology
Background:
- Beryllium salts are known to inhibit DNA replication and cell division.
- Previous studies showed beryllium inhibits rat hepatic cells in vivo and BL9L cells in vitro during G1 phase.
Purpose of the Study:
- To investigate the effect of beryllium sulfate (BeSO4) on the expression of the c-myc proto-oncogene in BL9L cells.
- To determine if beryllium's inhibition of cell division impacts c-myc gene expression.
Main Methods:
- Synchronized BL9L cells were exposed to inhibitory concentrations of BeSO4.
- c-myc mRNA levels were measured using techniques not specified in the abstract.
- Expression of the H-2Kb gene was monitored as a control.
Main Results:
- BeSO4 exposure did not impair c-myc expression in BL9L cells.
- Increased c-myc mRNA levels during G1 phase were maintained by BeSO4.
- Other metal salts (ZnSO4, ZrSO4) did not affect c-myc expression.
- H-2Kb gene expression remained unaltered by BeSO4.
Conclusions:
- Beryllium ions (Be2+) prevent the down-regulation of c-myc expression in serum-stimulated BL9L cells.
- This effect appears to result from modulation of the endogenous transcriptional control process for c-myc.
- Beryllium's impact on cell division may involve altered gene regulation rather than complete blockage.