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Updated: Jul 15, 2026
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Focus Formation: A Cell-based Assay to Determine the Oncogenic Potential of a Gene
Published on: December 31, 2014
A ras-related gene with transformation suppressor activity.
H Kitayama1, Y Sugimoto, T Matsuzaki
1Laboratory of Molecular Oncology, Tsukuba Life Science Center, Ibaraki, Japan.
Cell
|January 13, 1989
Summary
Researchers identified the Krev-1 gene, which suppresses cancer cell growth and shares similarities with ras proteins. This gene is found across species and widely expressed, suggesting a crucial role in tissue regulation.
Area of Science:
- Molecular biology
- Cell biology
- Genetics
Background:
- Kirsten sarcoma virus transformation of NIH/3T3 cells leads to a malignant phenotype.
- Identifying genes that can reverse this transformation is crucial for understanding cancer biology.
Purpose of the Study:
- To isolate and characterize a cDNA clone with the ability to reverse the transformed phenotype of NIH/3T3 cells.
- To investigate the function and evolutionary conservation of the identified gene.
Main Methods:
- Isolation of a cDNA expression library from human fibroblasts.
- Transfection of NIH/3T3 cells with the Krev-1 cDNA clone.
- Analysis of mRNA levels and phenotypic suppression.
- Amino acid sequence comparison with known proteins.
- Southern blot analysis to detect homologous sequences in other species.
Main Results:
- A 1.8 kb cDNA clone, Krev-1, was isolated and demonstrated revertant-inducing activity.
- Krev-1 transfectants showed a correlation between specific mRNA levels and suppression of the transformed phenotype.
- The Krev-1 cDNA encodes a 21,000-dalton protein with approximately 50% amino acid identity to ras proteins.
- Homologous Krev-1 sequences were detected in mouse, rat, and chicken DNA, with ubiquitous expression in rat organs.
Conclusions:
- The Krev-1 gene plays a significant role in various tissues.
- Krev-1 may be involved in the negative regulation of cell growth in specific cell types.
- The structural similarity to ras proteins suggests a potential role in cellular signaling pathways related to growth control.
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Genes usually encode proteins necessary for the proper functioning of a healthy cell. Mutations can often cause changes to the gene expression pattern, thereby altering the phenotype.
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