Single-molecule measurements of viral ssRNA packaging
- Kalle J. Hanhijärvi1,
- Gabija Ziedaite2,
- Dennis H. Bamford2,3,
- Edward Hæggström1 and
- Minna M. Poranen2
- 1Department of Physics, University of Helsinki, Helsinki 00014, Finland
- 2Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
- 3Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
- Corresponding author: kalle.hanhijarvi{at}helsinki.fi
Abstract
Genome packaging of double-stranded RNA (dsRNA) phages has been widely studied using biochemical and molecular biology methods. We adapted the existing in vitro packaging system of one such phage for single-molecule experimentation. To our knowledge, this is the first attempt to study the details of viral RNA packaging using optical tweezers. Pseudomonas phage φ6 is a dsRNA virus with a tripartite genome. Positive-sense (+) single-stranded RNA (ssRNA) genome precursors are packaged into a preformed procapsid (PC), where negative strands are synthesized. We present single-molecule measurements of the viral ssRNA packaging by the φ6 PC. Our data show that packaging proceeds intermittently in slow and fast phases, which likely reflects differences in the unfolding of the RNA secondary structures of the ssRNA being packaged. Although the mean packaging velocity was relatively low (0.07–0.54 nm/sec), packaging could reach 4.62 nm/sec during the fast packaging phase.
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Article is online at http://www.rnajournal.org/cgi/doi/10.1261/rna.057471.116.
- Received May 12, 2016.
- Accepted October 27, 2016.
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