RNA aptamers specifically interact with the prion protein PrP

Area of Science:

• Biochemistry
• Molecular Biology
• Neuroscience

Background:

• Prion diseases, or transmissible spongiform encephalopathies (TSEs), are fatal neurodegenerative disorders.
• Accurate diagnostics for TSEs are crucial for early detection and management.
• Prion protein (PrP) is a key biomarker in these diseases.

Purpose of the Study:

• To isolate and characterize RNA aptamers that specifically bind to the prion protein (PrP).
• To identify the specific region and structural motif of PrP recognized by these aptamers.
• To evaluate the potential of these aptamers as diagnostic tools for TSEs.

Main Methods:

• Isolation of RNA aptamers against recombinant Syrian golden hamster prion protein (rPrP23-231).
• Mapping of the aptamer-binding site to the N-terminal region (amino acids 23-52) of PrP.
• Structural analysis suggesting G-quartet motifs in aptamers are crucial for binding.
• Validation of specificity using brain homogenates from various species and PrP knockout mice.
• Testing aptamer binding with PrP27-30 from scrapie-infected mice.

Main Results:

• RNA aptamers were successfully isolated that specifically bind to rPrP23-231.
• The N-terminal region (amino acids 23-52) of PrP was identified as the interaction site.
• G-quartet structures within the RNA aptamers were found to be essential for PrP recognition.
• Aptamers demonstrated specific binding to PrP in wild-type mouse, hamster, and cattle brain homogenates, but not in PrP knockout mice.
• No recognition of PrP27-30 in scrapie-infected mouse brain homogenates was observed.

Conclusions:

• RNA aptamers targeting the N-terminal G-quartet motif of PrP have been developed.
• These aptamers exhibit high specificity for PrP across different species.
• The findings suggest RNA aptamers are a promising first step towards developing novel diagnostic assays for TSEs.