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A selection system for human apoptosis inhibitors using yeast
W Greenhalf1, J Lee, B Chaudhuri
1Oncology Research, Novartis Pharma AG, Basel, Switzerland. greenhaf@liverpool.ac.uk
Abstract:
Apoptosis is a regulated series of events which leads to the death and elimination of mammalian cells during development or in disease control. It is regulated in part by members of the Bcl-2 family of genes. Some of these stimulate cell death, while others prevent it. Expression of one of these death inducers, Bax-alpha (Bax), in the yeast Saccharomyces cerevisiae induces growth arrest and subsequently can cause cell death. Proteins of the Bcl-2 family that are known to inhibit apoptosis in mammalian cells overcome Bax-induced growth arrest in yeast. We describe here a system for isolation of human genes that are able to overcome Bax sensitivity in yeast. Two novel proteins, identified with this system, have been named 'Bax antagonists selected in saccharomyces' (BASS). These proteins not only overcome toxicity of Bax in yeast but also protect mammalian cells from apoptosis that is induced by staurosporine or Bax overexpression. We find that BASS2 is the more effective of the two genes.
Insights
Researchers identified novel human genes, Bax antagonists selected in Saccharomyces (BASS), that protect cells from apoptosis. BASS proteins overcome toxicity in yeast and safeguard mammalian cells from programmed cell death.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Apoptosis is a crucial cellular process regulated by the Bcl-2 gene family.
- Bcl-2 family members either promote or inhibit apoptosis.
- Bax-alpha (Bax), a pro-apoptotic protein, induces growth arrest and cell death in yeast.
Purpose of the Study:
- To develop a system for isolating human genes that counteract Bax-induced toxicity in yeast.
- To identify and characterize novel proteins that regulate apoptosis.
Main Methods:
- Utilized yeast Saccharomyces cerevisiae as a model system to screen for human genes.
- Expressed Bax-alpha in yeast to induce sensitivity.
- Screened for human genes that confer resistance to Bax-induced toxicity.
Main Results:
- Identified two novel human genes, named Bax antagonists selected in Saccharomyces (BASS).
- BASS proteins successfully overcame Bax-induced toxicity and growth arrest in yeast.
- BASS proteins demonstrated protective effects against apoptosis in mammalian cells induced by staurosporine or Bax overexpression.
- BASS2 was found to be more potent than BASS1.
Conclusions:
- The yeast system is effective for isolating apoptosis-regulating genes.
- BASS proteins represent a new class of apoptosis inhibitors.
- BASS proteins have potential therapeutic applications in preventing mammalian cell death.