Related Experiment Video

Updated: Aug 7, 2026

Using Reverse Genetics to Manipulate the NSs Gene of the Rift Valley Fever Virus MP-12 Strain to Improve Vaccine Safety and Efficacy
09:13

Using Reverse Genetics to Manipulate the NSs Gene of the Rift Valley Fever Virus MP-12 Strain to Improve Vaccine Safety and Efficacy

Published on: November 1, 2011

Characterization of the 1918 "Spanish" influenza virus matrix gene segment

Ann H Reid1, Thomas G Fanning, Thomas A Janczewski

  • 1Division of Molecular Pathology, Department of Cellular Pathology and Genetics, Armed Forces Institute of Pathology, Rockville, Maryland 20850-3125, USA. Reid@afip.osd.mil

Journal of Virology
|October 9, 2002
PubMed

Insights

The 1918 influenza A virus matrix genes (M1 and M2) were sequenced, revealing unique adaptations. Phylogenetic analysis suggests these genes were mammalian-adapted and present in human strains before 1918.

Area of Science:

  • Virology
  • Molecular Biology
  • Genetics

Background:

  • Influenza A virus RNA segment 7 encodes matrix proteins M1 and M2.
  • The 1918 pandemic virus caused significant global mortality.
  • Understanding viral evolution is crucial for pandemic preparedness.

Purpose of the Study:

  • To sequence and analyze the matrix genes (M1 and M2) of the 1918 influenza A virus.
  • To compare the 1918 matrix gene sequences with other influenza strains.
  • To infer the evolutionary origins and adaptations of the 1918 virus matrix segment.

Main Methods:

  • RNA sequencing of influenza A virus segment 7 from the 1918 pandemic strain.
  • Bioinformatic analysis of open reading frames for M1 and M2 genes.
  • Phylogenetic analysis to determine evolutionary relationships.
  • Comparison of amino acid sequences with conserved domains and known pathogenic markers.

Main Results:

  • The 1918 influenza A virus matrix segment 7 sequence is unique among previously sequenced strains.
  • Key functional domains (M1 RNA-binding, M2 transmembrane) are conserved.
  • No specific amino acid changes linked to high pathogenicity in animal models were identified in the 1918 strain.
  • Phylogenetic analyses indicate mammalian adaptation and similarity to the common ancestor of human and swine strains.
  • Four amino acids in the M2 extracellular domain match mammalian strains, suggesting pre-1918 circulation in humans.

Conclusions:

  • The matrix segment of the 1918 influenza A virus shows evidence of mammalian adaptation.
  • The sequence is closely related to the ancestor of subsequent human and swine influenza strains.
  • The findings suggest the matrix segment may have circulated in human populations for years prior to the 1918 pandemic.

More Related Videos

Affinity Purification of Influenza Virus Ribonucleoprotein Complexes from the Chromatin of Infected Cells11:20

Affinity Purification of Influenza Virus Ribonucleoprotein Complexes from the Chromatin of Infected Cells

Published on: June 3, 2012

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

Related Concept Videos

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 for adaptive...
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...
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...
Influenza01:27

Influenza

Influenza is an acute, highly communicable viral disease that affects the respiratory tract and is responsible for seasonal epidemics worldwide. Influenza A is the most prevalent type associated with widespread outbreaks and is subtyped based on two surface glycoproteins: hemagglutinin (H) and neuraminidase (N), as in H1N1. These glycoproteins are essential for viral infectivity, transmission, and immune recognition. Transmission occurs primarily through respiratory droplets and contaminated...
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...
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...