Mapping of Prion Structures in the Yeast Rnq1

Area of Science:

• Biochemistry
• Molecular Biology
• Yeast Genetics

Background:

• The Rnq1 protein is a well-characterized yeast prion with a large, potentially prionogenic C-terminal region.
• Previous research suggested only the C-terminal 40 residues form the prion structure, but this is re-evaluated here.

Purpose of the Study:

• To map the actual and potential prion structures of Rnq1 and its C-terminal variants.
• To investigate the reliability of Rnq1-GFP fusions for studying prion properties.

Main Methods:

• Partial proteinase K digestion was used to analyze Rnq1 and its truncated variants in [RNQ+] yeast strains.
• Microscopic observation of aggregation patterns for Rnq1 hybrid proteins.

Main Results:

• Actual Rnq1 prion structures often differed from computational predictions and previous studies.
• Aggregation patterns of Rnq1 hybrids varied significantly from Sup35 prion aggregates.
• GFP fusion at the Rnq1 C-terminus inhibited prion formation, questioning its use in prior research.

Conclusions:

• The C-terminal region of Rnq1 involved in prion formation is more complex than previously thought.
• Rnq1-GFP fusions are not suitable for accurately studying Rnq1 prion characteristics.
• Findings necessitate a re-evaluation of existing yeast prion research methodologies.