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

• Published in: Viruses 2018-03, Vol.10 (4), p.150
• Main Authors: Hashemi, Hamidreza, Condurat, Alexandra-Larisa, Stroh-Dege, Alexandra, Weiss, Nadine, Geiss, Carsten, Pilet, Jill, Cornet Bartolomé, Carles, Rommelaere, Jean, Salomé, Nathalie, Dinsart, Christiane
• Format: Article
• Language: English
• Subjects: Amino acid sequence; Animals; Antibiotics; Binding sites; Capsid - metabolism; Capsid Proteins - metabolism; Cell culture; Cell Line; Cloning; Cytoplasm; Cytotoxicity; DNA biosynthesis; DNA polymerase; DNA, Viral - biosynthesis; DNA, Viral - metabolism; fitness mutants; Genetic Vectors - genetics; Genomes; H-1 parvovirus - genetics; H-1 parvovirus - growth & development; H-1 parvovirus - physiology; Humans; Infectivity; Internalization; Mutation; NS2 protein; Open Reading Frames - genetics; parvoviral vectors; Parvoviridae Infections - virology; Parvoviruses; Plasmids; Protein Processing, Post-Translational; Proteins; protoparvovirus H-1PV; Rats; Replication; Reproductive fitness; Transduction, Genetic; Viral Nonstructural Proteins - genetics; Viral Proteins - metabolism; Virus Attachment; Virus Internalization; Virus Release; Virus Replication; Viruses
• ISSN: 1999-4915; 1999-4915
• 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.