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Updated: Jun 25, 2026
High-throughput Screening for Protein-based Inheritance in S. cerevisiae
Published on: August 8, 2017
Inhibition of prion amplification by expression of dominant inhibitory mutants--a systematic insertion mutagenesis
Markus Geissen1, Harriet Mella, Armin Saalmüller
1Institute for Novel and Emerging Infectious Diseases at the Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany. martin.groschup@fli.bund.de
Abstract:
Until now it is still not clear which structural elements of the prion protein (PrP) are involved in its conversion process. Characterisation of these essential regions would help to understand the conversion process itself and might help to develop specific therapeutic approaches to inhibit PrP(res) formation by dominant inhibitory mutations. To address this important question 33 evenly spaced insertion mutants were generated spanning the entire sequence of the murine 3F4-tagged PrP. The mutants were expressed by retroviral transduction in three different scrapie infected cell lines (ScN2a; SMB[RC040]; SMB[22F]). The convertibility was affected not only by introducing the insertion in the putatively refolded region (aa100-170), but also in the C-terminus of PrP (up to aa214). Moreover, dominant inhibitory effects on conversion were observed for PrP-mutants at four distinguished regions (aa100-112; aa130-154; aa166-172, aa196-200). Computer based structural analysis revealed that these segments were organized in two structurally clearly separated regions supporting the idea that they could function as protein-protein interaction sites which are necessary during seed formation.
Insights
Identifying key prion protein (PrP) structural regions is crucial for understanding conversion and developing therapies. This study mapped essential PrP segments involved in scrapie conversion using insertion mutants in infected cells.
Area of Science:
- Neuroscience
- Molecular Biology
- Biochemistry
Background:
- The structural elements of the prion protein (PrP) critical for its conversion into pathogenic forms remain unclear.
- Understanding these elements is vital for developing therapeutic strategies against prion diseases.
Purpose of the Study:
- To identify specific structural regions of the prion protein (PrP) involved in the conversion process.
- To investigate the role of these regions in the formation of protease-resistant PrP (PrP(res)) and explore potential therapeutic targets.
Main Methods:
- Generation of 33 evenly spaced insertion mutants across the entire murine 3F4-tagged PrP sequence.
- Expression of PrP mutants in three distinct scrapie-infected cell lines (ScN2a, SMB[RC040], SMB[22F]) via retroviral transduction.
- Analysis of mutant convertibility and dominant inhibitory effects on PrP(res) formation, coupled with computer-based structural analysis.
Main Results:
- PrP convertibility was significantly affected by insertions in the putative refolded region (aa100-170) and the C-terminus (up to aa214).
- Four distinct regions (aa100-112; aa130-154; aa166-172, aa196-200) exhibited dominant inhibitory effects on prion conversion.
- Structural analysis indicated these functionally important segments are organized into two distinct regions, suggesting roles as protein-protein interaction sites during seed formation.
Conclusions:
- Specific structural regions within the prion protein, particularly aa100-170 and the C-terminus, are essential for its conversion.
- Identified inhibitory regions (aa100-112; aa130-154; aa166-172, aa196-200) offer potential targets for therapeutic interventions aimed at inhibiting PrP(res) formation.
- The findings support a model where distinct structural domains mediate protein-protein interactions critical for prion seed formation.
