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Baculovirus-based genetic screen for antiapoptotic genes identifies a novel IAP
1Departments of Molecular Oncology, Genentech Inc., South San Francisco, California 94080, USA.
Abstract:
The prototype baculovirus, Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) expresses p35, a potent anti cell-death gene that promotes the propagation of the virus by blocking host cell apoptosis. Infection of insect Sf-21 cells with AcMNPV lacking p35 induces apoptosis. We have used this pro-apoptotic property of the p35 null virus to screen for genes encoding inhibitors of apoptosis that rescue cells infected with the p35 defective virus. We report here the identification of Tn-IAP1, a novel member of the IAP family of cell death inhibitors. Tn-IAP1 blocks cell death induced by p35 null AcMNPV, actinomycin D, and Drosophila cell-death inducers HID and GRIM. Given the conserved nature of the cell death pathway, this genetic screen can be used for rapid identification of novel inhibitors of apoptosis from diverse sources.
Insights
Researchers identified Tn-IAP1, a novel inhibitor of apoptosis, using a baculovirus genetic screen. This discovery aids in finding new cell death inhibitors for various applications.
Area of Science:
- Molecular Biology
- Virology
- Cell Biology
Background:
- Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) utilizes the p35 gene to inhibit host cell apoptosis, crucial for viral propagation.
- AcMNPV lacking the p35 gene induces apoptosis in infected insect cells, providing a tool for genetic screening.
Purpose of the Study:
- To identify novel genes encoding inhibitors of apoptosis (IAPs) using a pro-apoptotic p35-null AcMNPV.
- To characterize the function of newly identified IAPs in blocking programmed cell death.
Main Methods:
- A genetic screen employing a p35-null AcMNPV was used to identify genes that rescue Sf-21 cells from apoptosis.
- The identified gene, Tn-IAP1, was characterized for its ability to inhibit cell death induced by various stimuli.
Main Results:
- The novel IAP family member, Tn-IAP1, was identified through the genetic screen.
- Tn-IAP1 demonstrated the ability to block apoptosis induced by p35-null AcMNPV, actinomycin D, and Drosophila cell-death inducers (HID and GRIM).
Conclusions:
- Tn-IAP1 is a functional inhibitor of apoptosis with conserved activity across different death pathways.
- The developed genetic screening method using p35-null baculovirus is effective for discovering novel apoptosis inhibitors from diverse sources.