Related Experiment Video

Updated: Oct 4, 2026

Generation and Assembly of Virus-Specific Nucleocapsids of the Respiratory Syncytial Virus
09:08

Generation and Assembly of Virus-Specific Nucleocapsids of the Respiratory Syncytial Virus

Published on: July 27, 2021

Cooperation of an RNA packaging signal and a viral envelope protein in coronavirus RNA packaging

K Narayanan1, S Makino

  • 1Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, Texas 77555-1019, USA.

Journal of Virology
|September 5, 2001
PubMed

Insights

Mouse hepatitis virus (MHV) selectively packages mRNA 1 using its M protein and a specific RNA packaging signal. This signal mediates M protein interaction, ensuring efficient viral RNA packaging into new virions.

Area of Science:

  • Virology
  • Molecular Biology
  • Genetics

Background:

  • Murine coronavirus (MHV) produces multiple mRNAs, but only mRNA 1 is packaged into virions.
  • MHV N protein binds all viral mRNAs, while M protein selectively binds mRNA 1.
  • A cis-acting RNA packaging signal is crucial for MHV RNA packaging.

Purpose of the Study:

  • To investigate if the packaging signal in mRNA 1 mediates the selective interaction with M protein.
  • To determine the role of the packaging signal in specific RNA packaging into MHV particles.

Main Methods:

  • Testing M protein interaction with RNAs containing or lacking the packaging signal.
  • Analyzing the packaging efficiency of RNAs that interact with M protein.
  • Utilizing MHV defective interfering RNAs and non-MHV RNA transcripts.

Main Results:

  • M protein selectively interacted with RNAs possessing the MHV packaging signal, irrespective of N protein binding.
  • Only RNAs that selectively interacted with M protein were efficiently packaged into MHV particles.
  • The packaging signal was identified as the mediator of selective M protein-RNA interaction.

Conclusions:

  • The MHV packaging signal dictates the selective M protein-RNA interaction, driving specific RNA packaging.
  • This study provides the first evidence for an RNA virus where an envelope protein and packaging signal jointly ensure selective RNA packaging into virions.

More Related Videos

Production of a SARS-CoV-2 Virus-Like-Particle System to Investigate Viral Life Cycles In Vitro09:26

Production of a SARS-CoV-2 Virus-Like-Particle System to Investigate Viral Life Cycles In Vitro

Published on: June 6, 2025

Bacterial Artificial Chromosomes: A Functional Genomics Tool for the Study of Positive-strand RNA Viruses12:20

Bacterial Artificial Chromosomes: A Functional Genomics Tool for the Study of Positive-strand RNA Viruses

Published on: December 29, 2015

Related Concept Videos

Coronavirus01:29

Coronavirus

Coronaviruses, including the severe acute respiratory syndrome coronavirus (SARS-CoV), are enveloped viruses characterized by their single-stranded, positive-sense RNA genome and helical nucleocapsid structure. The hallmark of these viruses is their club-shaped spike (S) glycoproteins that protrude from the viral envelope, facilitating attachment to host cells. Typically, coronaviruses infect the upper respiratory tract, often causing mild or asymptomatic disease. However, certain strains like...
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...
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 stands for...
Viral Structure00:56

Viral Structure

Viruses are extraordinarily diverse in shape and size, but they all have several structural features in common. All viruses have a core that contains a DNA- or RNA-based genome. The core is surrounded by a protective coat of proteins called the capsid. The capsid is composed of subunits called capsomeres. The capsid and genome-containing core are together known as the nucleocapsid.
Inhibitors Of Virion Release01:25

Inhibitors Of Virion Release

Viral replication and dissemination rely on efficient mechanisms for host cell entry, genome replication, assembly, and release. Influenza viruses, such as types A and B, are negative-sense single-stranded RNA viruses with a segmented genome, that depend on two critical surface glycoproteins to carry out these processes: hemagglutinin (HA) and neuraminidase (NA). HA initiates infection by binding to sialic acid residues on the surface of host epithelial cells, facilitating receptor-mediated...
Retrovirus Life Cycles01:10

Retrovirus Life Cycles

Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the retrovirus to...