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Molecular cloning and chromosome mapping of the human gene encoding protein phosphotyrosyl phosphatase 1B
S Brown-Shimer1, K A Johnson, J B Lawrence
1Applied bioTechnology, Inc., Cambridge, MA 02142.
Abstract:
The inactivation of growth suppressor genes appears to play a major role in the malignant process. To assess whether protein phosphotyrosyl phosphatases (protein-tyrosine-phosphate phosphohydrolase, EC 3.1.3.48) function as growth suppressors, we have isolated a cDNA clone encoding human protein phosphotyrosyl phosphatase 1B for structural and functional characterization. The translation product deduced from the 1305-nucleotide open reading frame predicts a protein containing 435 amino acids and having a molecular mass of 49,966 Da. The amino-terminal 321 amino acids deduced from the cDNA sequence are identical to the empirically determined sequence of protein phosphotyrosyl phosphatase 1B. [Charbonneau, H., Tonks, N. K., Kumar, S., Diltz, C. D., Harrylock, M., Cool, D. E., Krebs, E. G., Fischer, E. H. & Walsh, K. A. (1989) Proc. Natl. Acad. Sci. USA 86, 5252-5256]. A genomic clone has been isolated and used in an in situ hybridization to banded metaphase chromosomes to determine that the gene encoding protein phosphotyrosyl phosphatase 1B maps as a single-copy gene to the long arm of chromosome 20 in the region q13.1-q13.2.
Insights
Researchers investigated protein phosphotyrosyl phosphatase 1B (PP1B) as a potential growth suppressor. They characterized the PP1B gene, finding it maps to chromosome 20, offering insights into cancer development.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Inactivation of growth suppressor genes is crucial in cancer.
- Protein phosphotyrosyl phosphatases (protein-tyrosine-phosphate phosphohydrolase, EC 3.1.3.48) are investigated for their role in regulating cell growth.
Purpose of the Study:
- To determine if protein phosphotyrosyl phosphatases function as tumor suppressors.
- To isolate and characterize the cDNA encoding human protein phosphotyrosyl phosphatase 1B (PP1B).
Main Methods:
- Isolation of a cDNA clone for human PP1B.
- Deduction of protein sequence from the cDNA open reading frame.
- In situ hybridization to map the PP1B gene on human chromosomes.
Main Results:
- The PP1B cDNA sequence predicts a 435-amino acid protein (49,966 Da).
- The deduced amino-terminal sequence matches empirical data for PP1B.
- The PP1B gene is located on chromosome 20, region q13.1-q13.2, as a single-copy gene.
Conclusions:
- Protein phosphotyrosyl phosphatase 1B is structurally and functionally characterized.
- The gene encoding PP1B is mapped to a specific chromosomal location, aiding further research into its role in growth suppression and malignancy.