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PTEN affects cell size, cell proliferation and apoptosis during Drosophila eye development
1Howard Hughes Medical Institute and Department of Genetics, Yale University School of Medicine, Boyer Center for Molecular Medicine, New Haven, CT 06536-0812, USA.
Abstract:
Mutations in the tumor suppressor gene PTEN (MMAC1/TEP1) are associated with a large number of human cancers and several autosomal-dominant disorders. Mice mutant for PTEN die at early embryonic stages and the mutant embryonic fibroblasts display decreased sensitivity to cell death. Overexpression of PTEN in different mammalian tissue culture cells affects various processes including cell proliferation, cell death and cell migration. We have characterized the Drosophila PTEN gene and present evidence that both inactivation and overexpression of PTEN affect cell size, while overexpression of PTEN also inhibits cell cycle progression at early mitosis and promotes cell death during eye development in a context-dependent manner. Furthermore, we have shown that PTEN acts in the insulin signaling pathway and all signals from the insulin receptor can be antagonized by either Drosophila or human PTEN, suggesting a potential means for alleviating symptoms associated with altered insulin signaling.
Insights
The tumor suppressor gene PTEN is crucial for cell size and survival. Inactivation or overexpression of PTEN impacts cell cycle and promotes cell death, particularly in the eye during development.
Area of Science:
- Genetics and Molecular Biology
- Developmental Biology
- Cancer Research
Background:
- Mutations in the PTEN (Phosphatase and tensin homolog) tumor suppressor gene are linked to numerous human cancers and genetic disorders.
- PTEN-deficient mice exhibit embryonic lethality, and their fibroblasts show reduced apoptosis.
- PTEN's role in mammalian cells influences proliferation, cell death, and migration.
Purpose of the Study:
- To investigate the function of the Drosophila PTEN gene in cellular processes.
- To determine the effects of PTEN gene inactivation and overexpression on cell size, cell cycle, and cell death.
- To explore PTEN's interaction with the insulin signaling pathway.
Main Methods:
- Gene characterization of Drosophila PTEN.
- Analysis of cell size, cell cycle progression, and cell death in response to PTEN manipulation.
- Investigating PTEN's role in the insulin signaling pathway using Drosophila models.
Main Results:
- Both PTEN gene inactivation and overexpression alter cell size in Drosophila.
- Overexpression of PTEN inhibits cell cycle progression at early mitosis and induces context-dependent cell death during eye development.
- Drosophila and human PTEN antagonize insulin receptor signaling, indicating PTEN's conserved role in this pathway.
Conclusions:
- Drosophila PTEN plays a significant role in regulating cell size, cell cycle, and cell death.
- PTEN functions as a negative regulator within the insulin signaling pathway.
- These findings suggest PTEN as a potential therapeutic target for conditions involving aberrant insulin signaling.