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Published on: September 11, 2013
Context-Dependent Tumorigenic Effect of Testis-Specific Mitochondrial Protein Tiny Tim 2 in Drosophila Somatic
Cristina Molnar1, Anxela Louzao1, Cayetano Gonzalez1,2
1Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain.
Abstract:
We have undertaken a study towards understanding the effect of ectopic expression of testis proteins in the soma in Drosophila. Here, we show that in the larval neuroepithelium, ectopic expression of the germline-specific component of the inner mitochondrial translocation complex tiny tim 2 (ttm2) brings about cell autonomous hyperplasia and extension of G2 phase. In the wing discs, cells expressing ectopic ttm2 upregulate Jun N-terminal kinase (JNK) signaling, present extended G2, become invasive, and elicit non-cell autonomous G2 extension and overgrowth of the wild-type neighboring tissue. Ectopic tomboy20, a germline-specific member of the outer mitochondrial translocation complex is also tumorigenic in wing discs. Our results demonstrate the tumorigenic potential of unscheduled expression of these two testis proteins in the soma. They also show that a unique tumorigenic event may trigger different tumor growth pathways depending on the tissular context.
Insights
Ectopic expression of testis proteins tiny tim 2 (ttm2) and tomboy20 in Drosophila soma causes cell overgrowth and invasive behavior. These findings highlight the tumorigenic potential of germline proteins in somatic tissues, influencing tumor pathways.
Area of Science:
- Developmental Biology
- Cell Biology
- Genetics
Background:
- Germline proteins typically function in reproductive cells.
- Somatic cells have distinct regulatory mechanisms compared to germline cells.
- Mitochondrial translocation complexes are crucial for organelle function.
Purpose of the Study:
- To investigate the effects of ectopic expression of germline-specific testis proteins in somatic tissues of Drosophila.
- To determine the impact of these proteins on cell proliferation, cell cycle progression, and tissue overgrowth.
- To explore the potential tumorigenic role of unscheduled germline protein expression in somatic contexts.
Main Methods:
- Utilizing Drosophila melanogaster as a model organism.
- Employing genetic manipulation for ectopic expression of testis proteins (ttm2 and tomboy20) in somatic tissues (larval neuroepithelium and wing discs).
- Analyzing cell-autonomous and non-cell-autonomous effects, including hyperplasia, G2 phase extension, JNK signaling activation, and invasive behavior.
Main Results:
- Ectopic expression of ttm2 in larval neuroepithelium induced cell-autonomous hyperplasia and G2 phase extension.
- In wing discs, ectopic ttm2 upregulated JNK signaling, caused G2 extension, invasiveness, and non-cell-autonomous overgrowth of neighboring wild-type tissue.
- Ectopic expression of tomboy20 in wing discs also demonstrated tumorigenic potential.
Conclusions:
- Unscheduled expression of testis proteins ttm2 and tomboy20 in the soma exhibits tumorigenic potential in Drosophila.
- The tumorigenic effects are context-dependent, with different tissular environments potentially triggering distinct tumor growth pathways.
- These findings underscore the importance of strict germline-soma separation for preventing aberrant growth and tumorigenesis.
