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Organization and expression of the mouse MTH1 gene for preventing transversion mutation
H Igarashi1, T Tsuzuki, T Kakuma
1Department of Biochemistry, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-82, Japan.
The Journal of Biological Chemistry
|February 7, 1997
Summary
Mouse mutT homologue 1 (MTH1) gene, encoding 8-oxo-dGTPase, was isolated and characterized. This enzyme prevents mutations by hydrolyzing 8-oxo-dGTP, safeguarding DNA integrity.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- 8-oxo-7,8-dihydrodeoxyguanosine triphosphatase (8-oxo-dGTPase) regulates spontaneous mutagenesis by hydrolyzing 8-oxo-dGTP.
- Preventing misincorporation of 8-oxo-dGTP prevents A:T to C:G transversion mutations.
Purpose of the Study:
- To isolate and characterize the mouse genomic sequence encoding 8-oxo-dGTPase.
- To elucidate the structure and promoter region of the MTH1 gene.
- To investigate the transcriptional regulation of the MTH1 gene.
Main Methods:
- Isolation and characterization of the mouse MTH1 gene and pseudogene.
- Analysis of the gene's promoter region (GC-rich, AP-1/AP-2 sites, no TATA box).
- Primer extension and S1 mapping to identify transcription initiation sites.
- Reporter gene assays (chloramphenicol acetyltransferase) with deletion analysis in NIH 3T3 cells.
Main Results:
- The mouse MTH1 gene comprises at least five exons and spans ~9 kb.
- Multiple transcription initiation sites were identified, with a major site at +1.
- A core promoter region (-321 to +9) and a transcription-stimulating region (+352 to +525) were identified.
Conclusions:
- The MTH1 gene structure and promoter elements involved in its transcriptional regulation have been elucidated.
- Understanding MTH1 regulation provides insights into DNA repair mechanisms and mutagenesis control.
- The identified promoter regions are crucial for controlling MTH1 gene expression.