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Characterization of multiple transcripts and isoforms derived from the mouse protein tyrosine phosphatase gene Ptprr
Renato G S Chirivi1, Gönül Dilaver, Rinske van de Vorstenbosch
1Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, University of Nijmegen, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands.
Genes to Cells : Devoted to Molecular & Cellular Mechanisms
|October 6, 2004
Summary
The mouse Ptprr gene generates diverse protein tyrosine phosphatase PTPRR isoforms. This complexity arises from alternative promoters, splicing, and translation start sites, influencing protein function and localization.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Organismal complexity increases with alternative splicing, promoters, and translation start sites.
- Four mouse cDNAs (PTPBR7, PTP-SL, PTPPBSgamma+, PTPPBSgamma-) encode identical protein tyrosine phosphatase PTPRR catalytic domains but differ in 5' regions.
Purpose of the Study:
- Investigate the genomic origin and coding potential of mouse PTPRR transcripts.
- Elucidate the interrelationship between different PTPRR cDNA variants.
Main Methods:
- Gene mapping of mouse Ptprr on chromosome 10.
- Northern and RT-PCR analyses for differential gene expression.
- Transfection studies and AUG codon mutagenesis to identify translation initiation sites.
Main Results:
- Ptprr exons span 260 kbp on chromosome 10.
- PTP-SL and PTPPBSgamma-specific transcription start sites identified within introns.
- Differential expression patterns observed for distinct promoters.
- Multiple translation initiation sites utilized in PTP-SL and PTPPBSgamma transcripts.
- Resulting PTPRR protein isoforms (72, 60, 42, 37 kDa) exhibit varied N-terminal lengths and subcellular localizations (receptor-like, membrane-associated, cytosolic).
Conclusions:
- Mouse Ptprr gene produces multiple protein isoforms via distinct promoters, alternative splicing, and differential translation initiation.
- These findings provide a foundation for exploring the physiological roles of PTPRR proteins.