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Two lck transcripts containing different 5' untranslated regions are present in T cells
A F Voronova1, H T Adler, B M Sefton
1Molecular Biology and Virology Laboratory, Salk Institute, San Diego, California 92138.
Molecular and Cellular Biology
|December 1, 1987
Summary
Elevated p56 extsubscript{lck} (leukocyte tyrosine kinase) expression in T cell lymphomas is driven by viral promoters. Normal T cells also show varied p56 extsubscript{lck} mRNA structures, suggesting multiple regulatory promoters.
Area of Science:
- Molecular Biology
- Immunology
- Oncology
Background:
- p56 extsubscript{lck} is a Src family tyrosine kinase.
- It is expressed at low levels in normal T cells.
- Elevated p56 extsubscript{lck} is found in specific T cell leukemia/lymphoma lines.
Purpose of the Study:
- Investigate the molecular basis for elevated p56 extsubscript{lck} expression in T cell lymphomas.
- Characterize the structure of p56 extsubscript{lck} mRNA in normal and malignant T cells.
- Determine the regulatory mechanisms controlling lck gene expression.
Main Methods:
- RNase protection assay to analyze mRNA structure.
- Comparison of lck mRNA in normal T cells and virus-induced thymoma cell lines (LSTRA, Thy19).
Main Results:
- Virus-induced thymoma cells (LSTRA, Thy19) exhibit 4-10 fold higher levels of a chimeric lck mRNA transcript.
- This chimeric transcript utilizes a viral promoter, explaining elevated lck mRNA.
- Normal T cells contain multiple lck mRNA species with different 5' untranslated regions, suggesting alternative promoters.
Conclusions:
- Viral promoter activation drives elevated p56 extsubscript{lck} in specific T cell lymphomas.
- The lck gene is expressed from at least two distinct promoters.
- These promoters may be subject to differential regulatory control, impacting T cell function and transformation.