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A c-ras-Ki oncogene is activated, amplified and overexpressed in a human osteosarcoma cell line
Abstract:
We present a characterization of an activated oncogene which we found to be present in DNA of the OHA osteosarcoma cell line. We identify this tumor oncogene which transforms Swiss mouse 3T3-cells, with c-ras-Ki 2, one of two known members of the Kirsten ras family of human proto-oncogenes. Its structural outlines are given and we show that: 1) a single point mutation causing a substitution of valine for glycine in codon 12 was found by DNA sequencing; 2) the c-ras-Ki gene is amplified and overexpressed in the original OHA tumor cells and its transformants and 3) the gene product is an abnormal form of the p21 protein.
Insights
Researchers identified an activated oncogene, c-ras-Ki 2, in osteosarcoma cells. This gene, mutated and amplified, leads to an abnormal p21 protein, driving tumor cell transformation.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Osteosarcoma is a malignant bone tumor.
- Proto-oncogenes can become activated oncogenes, driving cancer development.
- The Kirsten ras (Ki-ras) family are known proto-oncogenes implicated in various cancers.
Purpose of the Study:
- To characterize an activated oncogene found in the OHA osteosarcoma cell line.
- To identify the specific gene and its mutations responsible for tumor cell transformation.
- To investigate the expression and protein product of the identified oncogene.
Main Methods:
- DNA sequencing to identify point mutations.
- Gene amplification analysis.
- Western blot or similar techniques to analyze protein expression and function.
Main Results:
- The activated oncogene was identified as c-ras-Ki 2, a member of the Kirsten ras family.
- A single point mutation (Glycine to Valine at codon 12) was detected in the c-ras-Ki 2 gene.
- The c-ras-Ki 2 gene was found to be amplified and overexpressed in OHA cells and their transformants.
- An abnormal p21 protein product was observed, resulting from the mutated and overexpressed gene.
Conclusions:
- The identified c-ras-Ki 2 gene is an activated oncogene driving osteosarcoma.
- The specific point mutation and gene amplification contribute to the oncogenic phenotype.
- The abnormal p21 protein is likely responsible for the transformation of cells.