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Expression of human PKR protein kinase in transgenic mice
Warren Ladiges1, John Morton, Heather Hopkins
1Comparative Mouse Genomics Center, Nathan Shock Center for Excellence in the Biology of Aging, Department of Comparative Medicine, University of Washington, Seattle, WA 98195, USA. wladiges@u.washington.edu
Abstract:
There is a large amount of evidence describing the expression, interaction, and mode of activation of the human interferon (IFN)-mediated double-stranded RNA-activated protein kinase (PKR) gene. Studies from Pkr-null mice have defined the kinase as a transducer of dsRNA signals that converge on transcription, translation, and apoptotic programs involved in the innate resistance to viral infection. In vitro studies also suggest that PKR may possess important cell growth regulatory and tumor suppressor properties. However, the study of Pkr-null mice has not fully elucidated the role that the kinase plays in these processes, in part because of apparent redundancies in PKR-dependent and PKR-independent regulatory pathways. To overcome such limitations and to begin to examine the role of PKR in a complex biologic system, we have generated transgenic mice overexpressing wild-type human (Hu) PKR. HuPKR was expressed and active in various tissues and associated with a small body phenotype. Spleen cells from transgenic mice were resistant to apoptosis when treated with the genotoxic agent actinomycin D and showed a decrease in proliferation in response to concanavalin A (ConA) compared with spleen cells from wild-type control mice. The initial characterization of this transgenic mouse line suggests it may be useful as a model for investigating biology and diseases relative to a number of scientific disciplines.
Insights
Transgenic mice overexpressing human PKR exhibit a small body size and altered spleen cell responses. This model aids in studying PKR
Area of Science:
- Molecular Biology
- Immunology
- Genetics
Background:
- The human interferon (IFN)-mediated double-stranded RNA-activated protein kinase (PKR) is crucial for innate antiviral immunity.
- PKR acts as a signal transducer for double-stranded RNA (dsRNA), influencing transcription, translation, and apoptosis.
- In vitro studies suggest PKR has roles in cell growth regulation and tumor suppression, but its in vivo functions are not fully understood due to pathway redundancies.
Purpose of the Study:
- To investigate the in vivo role of PKR in a complex biological system.
- To generate and characterize transgenic mice overexpressing wild-type human PKR (HuPKR).
Main Methods:
- Generation of transgenic mice overexpressing human PKR.
- Analysis of HuPKR expression and activity in various tissues.
- Assessment of spleen cell apoptosis resistance to actinomycin D.
- Evaluation of spleen cell proliferation in response to concanavalin A (ConA).
Main Results:
- HuPKR was expressed and active in multiple tissues of the transgenic mice.
- Transgenic mice displayed a small body phenotype.
- Spleen cells from transgenic mice showed resistance to actinomycin D-induced apoptosis.
- Spleen cells from transgenic mice exhibited reduced proliferation in response to ConA compared to wild-type controls.
Conclusions:
- The generated transgenic mouse line serves as a valuable model for studying PKR biology.
- This model can be used to investigate PKR's role in various biological processes and diseases.
- The findings highlight PKR's involvement in cell growth, apoptosis, and immune responses.