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Cell-type-specific expression of mouse DNA polymerase beta-gene is regulated by silencer elements
M Yamaguchi1, Y Hayashi, K Ajiro
1Laboratory of Cell Biology, Aichi Cancer Center Research Institute, Nagoya, Japan.
Journal of Cellular Physiology
|November 1, 1989
Summary
Cell-type specific DNA polymerase beta gene expression is controlled by silencer elements. These silencers significantly repressed gene activity in NIH/3T3 cells but not in N18TG2 cells, explaining expression differences.
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- DNA polymerase beta is crucial for DNA repair.
- Differential gene expression underlies cell-type specific functions.
- Understanding gene regulation mechanisms is vital for cellular processes.
Purpose of the Study:
- To investigate the role of DNA polymerase beta-gene silencers in cell-type specific gene expression.
- To compare the function of these silencers in mouse neuroblastoma N18TG2 and NIH/3T3 cells.
Main Methods:
- RNA blot hybridization was used to quantify DNA polymerase beta-mRNA levels.
- Chloramphenicol acetyltransferase (CAT)-transient expression assays were performed.
- CAT plasmids with silencers linked to promoter-enhancers were utilized.
Main Results:
- N18TG2 cells showed a five-fold higher steady-state level of DNA polymerase beta-mRNA than NIH/3T3 cells.
- DNA polymerase beta-gene silencers repressed gene function in NIH/3T3 cells but had minimal effect in N18TG2 cells.
- Removing silencer elements in NIH/3T3 cells increased CAT expression, correlating with mRNA level differences.
Conclusions:
- Cell-type specific expression of the DNA polymerase beta gene is primarily regulated by silencer elements.
- The differential function of silencers in N18TG2 and NIH/3T3 cells explains the observed variations in gene expression.
- Silencer elements play a key role in controlling DNA polymerase beta gene activity across different cell types.