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The TPTE gene family: cellular expression, subcellular localization and alternative splicing
Caroline Tapparel1, Alexandre Reymond, Christophe Girardet
1Division of Medical Genetics, Centre Medical Universitaire, University of Geneva Medical School, 1, Rue Michel Servet CH-1211, Geneva, Switzerland.
Gene
|December 9, 2003
Summary
The Transmembrane Phosphatase with TEnsin homology (TPTE) gene family has multiple copies in humans, encoding proteins expressed in sperm cells. Novel alternatively spliced isoforms were identified, with no impact on cellular location.
Area of Science:
- Genetics
- Molecular Biology
- Cell Biology
Background:
- The human TPTE gene family encodes PTEN-related tyrosine phosphatases with transmembrane domains.
- Multiple TPTE gene copies are located on human chromosomes 13, 15, 21, 22, and Y.
- Functional proteins TPIP and TPTE are encoded by chromosome 13 and 21 copies, respectively, unlike the single mouse copy.
Purpose of the Study:
- To investigate the expression of TPTE and TPIP proteins in human reproductive cells.
- To identify and characterize novel alternatively spliced isoforms of TPTE and TPIP.
- To determine the subcellular localization of these isoforms and identify other expressed TPTE copies.
Main Methods:
- Chromosomal mapping to identify TPTE gene locations.
- Expression analysis in secondary spermatocytes and prespermatids.
- Co-immunofluorescence experiments for subcellular localization.
- Analysis of alternative splicing and retroviral LTR control.
Main Results:
- TPTE and TPIP proteins are expressed in secondary spermatocytes and/or prespermatids.
- Several novel alternatively spliced isoforms of TPTE and TPIP with varying transmembrane domains were identified.
- Subcellular localization was unaffected by the number of transmembrane domains.
- An additional expressed TPTE copy on chromosome 22, regulated by RTVL-H3 LTR, was identified.
Conclusions:
- The TPTE gene family exhibits complex organization and expression in human germ cells.
- Alternative splicing generates diverse protein isoforms without altering subcellular localization.
- A novel TPTE copy on chromosome 22 is transcriptionally regulated by a retroviral element.