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Characterization of a human transforming gene isolated from T24 bladder carcinoma cells
Abstract:
A human transforming gene present in T24 bladder carcinoma cells has been molecularly cloned. The transforming sequences have been located within a 4.6 kilo base pair (kbp) DNA fragment that transforms NIH/3T3 cells with a specific activity of 5 X 10(4) focus-forming units/pmol. Homologous sequences present in normal human DNA have also been molecularly cloned. Comparison of the restriction endonuclease maps of the normal and transforming genes did not reveal any significant differences. These results suggest that subtle molecular changes are responsible for the acquisition of malignant properties by this gene in T24 cells. The T24 oncogene was found to be unrelated to transforming genes present in a variety of human tumors other than bladder carcinomas. In contrast, the T24 oncogene is highly related to the onc genes of the BALB and Harvey strains of murine sarcoma viruses ( MSVs ). Preliminary characterization of the transcriptional and translational products of the T24 oncogene suggests that this gene is transcribed into a 1.2-kbp poly(A)-containing RNA whose translation yields a 23,000-dalton protein antigenically related to the transforming gene products of BALB and Harvey MSVs .
Insights
Researchers identified a human transforming gene in T24 bladder carcinoma cells. This oncogene, highly related to specific murine sarcoma viruses, shows subtle molecular changes linked to malignancy.
Area of Science:
- Molecular biology
- Oncogenesis
- Cancer genetics
Background:
- Human transforming genes play a crucial role in cellular transformation and cancer development.
- The T24 bladder carcinoma cell line harbors a specific transforming gene implicated in malignancy.
Purpose of the Study:
- To molecularly clone and characterize the transforming gene from T24 bladder carcinoma cells.
- To compare the cloned transforming gene with its normal human counterpart.
- To investigate the relationship of the T24 oncogene to other known oncogenes and its expression products.
Main Methods:
- Molecular cloning of transforming sequences from T24 cells and homologous sequences from normal human DNA.
- Restriction endonuclease mapping to compare normal and transforming genes.
- Analysis of transcriptional and translational products of the T24 oncogene.
Main Results:
- A 4.6 kilobase pair (kbp) DNA fragment containing transforming sequences was identified.
- No significant differences were found in restriction maps between the normal and transforming genes, suggesting subtle molecular alterations.
- The T24 oncogene is distinct from most other human tumor oncogenes but highly related to BALB and Harvey murine sarcoma virus oncogenes.
- The T24 oncogene is transcribed into a 1.2-kbp RNA, yielding a 23,000-dalton protein antigenically related to MSV transforming proteins.
Conclusions:
- Subtle molecular changes, rather than gross structural differences, likely contribute to the malignant properties of the T24 oncogene.
- The T24 oncogene represents a specific type of oncogene found in bladder carcinomas, sharing homology with viral oncogenes.
- The identified 23,000-dalton protein product may be involved in the oncogenic mechanism of T24 bladder carcinoma cells.