Mutations in the Non-Structural Protein-Coding Sequence of Protoparvovirus H-1PV Enhance the Fitness of the Virus and Show Key Benefits Regarding the Transduction Efficiency of Derived Vectors

Viruses. 2018 Mar 27;10(4):150. doi: 10.3390/v10040150.


Single nucleotide changes were introduced into the non-structural (NS) coding sequence of the H-1 parvovirus (PV) infectious molecular clone and the corresponding virus stocks produced, thereby generating H1-PM-I, H1-PM-II, H1-PM-III, and H1-DM. The effects of the mutations on viral fitness were analyzed. Because of the overlapping sequences of NS1 and NS2, the mutations affected either NS2 (H1-PM-II, -III) or both NS1 and NS2 proteins (H1-PM-I, H1-DM). Our results show key benefits of PM-I, PM-II, and DM mutations with regard to the fitness of the virus stocks produced. Indeed, these mutants displayed a higher production of infectious virus in different cell cultures and better spreading capacity than the wild-type virus. This correlated with a decreased particle-to-infectivity (P/I) ratio and stimulation of an early step(s) of the viral cycle prior to viral DNA replication, namely, cell binding and internalization. These mutations also enhance the transduction efficiency of H-1PV-based vectors. In contrast, the PM-III mutation, which affects NS2 at a position downstream of the sequence deleted in Del H-1PV, impaired virus replication and spreading. We hypothesize that the NS2 protein-modified in H1-PM-I, H1-PM-II, and H1-DM-may result in the stimulation of some maturation step(s) of the capsid and facilitate virus entry into subsequently infected cells.

Keywords: fitness mutants; parvoviral vectors; protoparvovirus H-1PV.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Capsid / metabolism
  • Capsid Proteins / metabolism
  • Cell Line
  • DNA, Viral / biosynthesis
  • DNA, Viral / metabolism
  • Genetic Vectors / genetics*
  • H-1 parvovirus / genetics
  • H-1 parvovirus / growth & development
  • H-1 parvovirus / physiology*
  • Humans
  • Mutation
  • Open Reading Frames / genetics*
  • Parvoviridae Infections / virology*
  • Protein Processing, Post-Translational
  • Rats
  • Transduction, Genetic*
  • Viral Nonstructural Proteins / genetics*
  • Viral Proteins / metabolism
  • Virus Attachment
  • Virus Internalization
  • Virus Release
  • Virus Replication


  • Capsid Proteins
  • DNA, Viral
  • Viral Nonstructural Proteins
  • Viral Proteins