Related Experiment Video

Updated: Oct 10, 2025

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

29.7K

A Point Mutation in the Human Parainfluenza Virus Type 2 Nucleoprotein Leads to Two Separate Effects on Virus

Naoki Saka1, Yusuke Matsumoto2, Keisuke Ohta1

  • 1Department of Microbiology, School of Medicine, Wakayama Medical Universitygrid.412857.d, Wakayama, Japan.

Journal of Virology
|December 8, 2021
PubMed

Insights

A mutation in human parainfluenza virus type 2 nucleoprotein (NP) affects viral RNA replication and rescue. This study recovered a viable virus with a second mutation, revealing distinct roles for the NP Q202 residue.

Area of Science:

  • Virology
  • Molecular Biology
  • Structural Biology

Background:

  • Paramyxovirus genomes follow the "rule of six," with nucleoprotein (NP) subunits binding six nucleotides.
  • The NP Q202 residue is the sole direct nucleotide base contact in the RNA binding groove.
  • NP mutations can impact viral RNA replication and virus rescue.

Purpose of the Study:

  • To investigate the dual phenotypes arising from the NP Q202 mutation in human parainfluenza virus type 2 (hPIV2).
  • To understand the role of NP Q202 in viral minigenome replication and virus rescue.
  • To elucidate the mechanism behind the rescue defect associated with the NP Q202 mutation.

Main Methods:

  • Site-directed mutagenesis to create NP Q202A mutant.
  • Cocultivation of transfected cells to recover rescued virus.
  • Analysis of viral RNA replication using minigenomes.
  • Identification of secondary mutations in rescued virus.

Main Results:

  • The NP Q202 mutation enabled minigenome replication with defective promoters but prevented standard virus rescue.
  • A viable rPIV2 with the NP Q202A mutation was recovered only after extensive cocultivation, requiring an additional NP I35L mutation.
  • The two observed phenotypes are likely caused by separate effects of the Q202 mutation.
  • The rescue defect may involve impaired incorporation of viral nucleocapsids into budding virions.

Conclusions:

  • The NP Q202 residue plays distinct roles in viral RNA replication and virus assembly/budding.
  • The 3' ends of nucleocapsids might interact with cell membranes for efficient virion budding.
  • Understanding these interactions is crucial for paramyxovirus life cycle research.
Keywords:
human parainfluenza virus type 2nucleoproteinreplication

More Related Videos

Multi-target Parallel Processing Approach for Gene-to-structure Determination of the Influenza Polymerase PB2 Subunit22:10

Multi-target Parallel Processing Approach for Gene-to-structure Determination of the Influenza Polymerase PB2 Subunit

Published on: June 28, 2013

13.4K
Pairwise Growth Competition Assay for Determining the Replication Fitness of Human Immunodeficiency Viruses11:19

Pairwise Growth Competition Assay for Determining the Replication Fitness of Human Immunodeficiency Viruses

Published on: May 4, 2015

11.3K

Related Concept Videos

Leaky Scanning02:28

Leaky Scanning

During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA.  Marilyn Kozak discovered that the sequence RCCAUGG (where R...
5.3K
Viral Mutations00:36

Viral Mutations

A mutation is a change in the sequence of bases of DNA or RNA in a genome. Some mutations occur during replication of the genome due to errors made by the polymerase enzymes that replicate DNA or RNA. Unlike DNA polymerase, RNA polymerase is prone to errors because it is not capable of “proofreading” its work. Viruses with RNA-based genomes, like HIV, therefore accrue mutations faster than viruses with DNA-based genomes. Because mutation and recombination provide the raw material...
34.6K
Viral Recombination00:57

Viral Recombination

Cells are sometimes infected by more than one virus at once. When two viruses disassemble to expose their genomes for replication in the same cell, similar regions of their genomes can pair together and exchange sequences in a process called recombination. Alternatively, viruses with segmented genomes can swap segments in a process called reassortment.
24.0K
Viruses with RNA Genomes01:29

Viruses with RNA Genomes

RNA viruses are categorized into positive-strand, negative-strand, or double-stranded groups based on their genomic structure and replication mechanisms. This classification dictates how they exploit host cellular machinery for protein synthesis and replication. Some RNA viruses also utilize reverse transcription as part of their life cycle, further diversifying their replication strategies.Positive-Strand RNA VirusesPositive-strand RNA viruses have genomes that function directly as messenger...
208
Mutations01:39

Mutations

Overview
85.4K
Size and Structure of Viral Genomes01:26

Size and Structure of Viral Genomes

Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. These genomes consist of either DNA or RNA and may be linear or circular. Additionally, they can be single-stranded or double-stranded, with each configuration affecting how the virus propagates within a host. RNA viruses, for instance, generally have smaller genomes than DNA viruses, a factor that contributes to their high mutation rates and...
224