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Isolation of Fidelity Variants of RNA Viruses and Characterization of Virus Mutation Frequency
18:10

Isolation of Fidelity Variants of RNA Viruses and Characterization of Virus Mutation Frequency

Published on: June 16, 2011

Mutations in VP1 of poliovirus specifically affect both encapsidation and release of viral RNA

K Kirkegaard1

  • 1Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder 80309.

Journal of Virology
|January 1, 1990
PubMed

Insights

Poliovirus mutants with defects in VP1 protein show impaired RNA release and entry into cells. These findings suggest RNA packaging and release are linked processes involving the VP1 amino terminus.

Area of Science:

  • Virology
  • Molecular Biology
  • Structural Biology

Background:

  • Poliovirus type 1 Mahoney mutants, VP1-101 and VP1-102, exhibit phenotypic defects.
  • These defects stem from deletions in the N-terminal region of the capsid protein VP1.
  • This VP1 region is internal to the virion and interacts with viral RNA.

Purpose of the Study:

  • To investigate the functional role of the VP1 amino terminus in poliovirus replication.
  • To determine the specific defects caused by mutations in the VP1 N-terminus.
  • To elucidate the relationship between RNA packaging, release, and viral morphogenesis.

Main Methods:

  • Characterization of poliovirus mutants VP1-101 and VP1-102.
  • Analysis of viral entry into CV1 and HeLa cells.
  • Plaque assays to assess viral replication.
  • Kinetics studies of RNA release and viral morphogenesis.

Main Results:

  • Mutants VP1-101 and VP1-102 showed reduced entry into CV1 cells and smaller plaque sizes.
  • Cell binding and conformational changes were unaffected, but RNA release was delayed.
  • VP1-102 mutant displayed defects in viral morphogenesis, with slower accumulation of RNA-containing particles.
  • VP1-101 mutation primarily affected RNA release, while VP1-102 affected both RNA release and encapsidation.

Conclusions:

  • The amino terminus of poliovirus VP1 is crucial for both RNA release and, in some cases, RNA encapsidation.
  • RNA packaging and RNA release are genetically linked but can be independently mutated.
  • These processes involve the VP1 N-terminal region, highlighting its importance in the viral life cycle.

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