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Human epithelial tumor antigen cDNA sequences. Differential splicing may generate multiple protein forms.
D H Wreschner1, M Hareuveni, I Tsarfaty
1Department of Microbiology, Faculty of Life Sciences, Tel Aviv University, Israel.
European Journal of Biochemistry
|May 20, 1990
Summary
Researchers have identified multiple forms of a human epithelial tumor antigen using complementary DNA (cDNA) sequencing. These diverse protein structures arise from alternative splicing, impacting their cellular localization and function in breast cancer.
Area of Science:
- Molecular Biology
- Cancer Research
- Biochemistry
Background:
- An epithelial antigen, aberrantly expressed in human breast tumors, was previously characterized only by a 20-amino-acid repeat motif.
- Understanding the full structure of this antigen is crucial for cancer diagnostics and therapeutics.
Purpose of the Study:
- To determine the complete amino acid sequences of various forms of the human epithelial tumor antigen.
- To elucidate the molecular mechanisms generating protein diversity for this antigen.
Main Methods:
- Isolation and sequencing of complementary DNAs (cDNAs) encoding the epithelial tumor antigen.
- Deduction of amino acid sequences from nucleotide sequences.
- Analysis of alternative splicing events in mRNA transcripts.
Main Results:
- Complete amino acid sequences for multiple forms of the epithelial tumor antigen were deduced from non-repeat cDNAs.
- Alternative splicing in regions flanking a central tandem repeat array generates protein diversity.
- Two distinct protein forms with varying signal peptides and a potential transmembrane region were identified.
Conclusions:
- The study defines the complete amino acid sequences of the epithelial tumor antigen, revealing multiple protein isoforms.
- Alternative splicing is the primary mechanism generating antigen diversity.
- These diverse protein forms likely exhibit distinct cellular and extracellular localizations, impacting their biological roles in breast cancer.