Ribosomal RNA Modulates Aggregation of thePodosporaPrion Protein HET-s

• Published in: International journal of molecular sciences Vol. 21; no. 17
• Main Authors: Pang, Yanhong, Kovachev, Petar Stefanov, Sanyal, Suparna
• Format: Journal Article
• Language: English
• Published: 2020
• Subjects: anserinaprion protein HET-s; PFAR; prion aggregation; ribosomal RNA
• ISSN: 1661-6596; 1422-0067
• DOI: 10.3390/ijms21176340

The role of the nucleic acids in prion aggregation/disaggregation is becoming more and more evident. Here, using HET-s prion from fungiPodospora anserina(P. anserina) as a model system, we studied the role of RNA, particularly of different domains of the ribosomal RNA (rRNA), in its aggregation process. Our results using Rayleigh light scattering, Thioflavin T (ThT) binding, transmission electron microscopy (TEM) and cross-seeding assay show that rRNA, in particular the domain V of the major rRNA from the large subunit of the ribosome, substantially prevents insoluble amyloid and amorphous aggregation of the HET-s prion in a concentration-dependent manner. Instead, it facilitates the formation of the soluble oligomeric "seeds", which are capable of promoting de novo HET-s aggregation. The sites of interactions of the HET-s prion protein on domain V rRNA were identified by primer extension analysis followed by UV-crosslinking, which overlap with the sites previously identified for the protein-folding activity of the ribosome (PFAR). This study clarifies a missing link between the rRNA-based PFAR and the mode of propagation of the fungal prions.