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Yeast As a Chassis for Developing Functional Assays to Study Human P53
Published on: August 4, 2019
Trp53-dependent DNA-repair is affected by the codon 72 polymorphism
1Laboratory of Molecular Carcinogenesis, National Cancer Centre, Singapore.
Abstract:
Trp53 is arguably the most critical tumour suppressor gene product that inhibits malignant transformation. Besides mutations that inactivate Trp53 functions, genetic polymorphisms have been suggested to be risk factors for cancer. A polymorphic site at codon 72 in exon 4 encodes either an arginine amino acid (Trp53(72R)) or a proline residue (Trp53(72P)). Previous studies have shown that the Trp53(72R) form is more efficient in apoptosis induction, whereas the Trp53(72P) form was suggested to induce G1 arrest better. Here we report that Trp53(72P) is more efficient than Trp53(72R) in specifically activating several Trp53-dependent DNA-repair target genes in several cellular systems. Moreover, using isogenic cell lines and several DNA-repair assays, we show that Trp53(72P) cells have a significantly higher DNA-repair capacity than the Trp53(72R) cells. Furthermore, Trp53(72P)-expressing cells exhibit reduced micronuclei formation compared to Trp53(72R)-expressing cells, suggesting that genomic instability is reduced in these cells. Together, the data highlight the functional differences between the Trp53 polymorphic variants, and suggest that their expression status may influence cancer risk.
Insights
The Trp53(72P) variant enhances DNA repair and reduces genomic instability more effectively than the Trp53(72R) variant. This suggests that Trp53 gene polymorphisms may influence cancer risk.
Area of Science:
- Molecular Biology
- Genetics
- Cancer Research
Background:
- TP53 is a crucial tumor suppressor gene.
- Genetic variations in TP53, such as the codon 72 polymorphism, are linked to cancer risk.
- The TP53(72R) and TP53(72P) variants have shown differential effects on apoptosis and cell cycle arrest.
Purpose of the Study:
- To investigate the functional differences between TP53(72R) and TP53(72P) variants.
- To determine the impact of these variants on DNA repair mechanisms and genomic stability.
Main Methods:
- Analysis of TP53-dependent DNA repair gene activation in different cellular systems.
- Utilizing isogenic cell lines and DNA repair assays.
- Assessing micronuclei formation to evaluate genomic instability.
Main Results:
- The TP53(72P) variant demonstrated superior activation of DNA repair genes compared to TP53(72R).
- Cells expressing TP53(72P) exhibited significantly enhanced DNA repair capacity.
- Reduced micronuclei formation in TP53(72P)-expressing cells indicated decreased genomic instability.
Conclusions:
- TP53(72P) is more effective than TP53(72R) in promoting DNA repair and maintaining genomic stability.
- The functional differences between TP53 polymorphic variants may play a role in modulating cancer risk.
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