Related Experiment Video

Updated: May 24, 2026

Affinity Purification of Influenza Virus Ribonucleoprotein Complexes from the Chromatin of Infected Cells
11:20

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

Published on: June 3, 2012

A nuclear export signal in the matrix protein of Influenza A virus is required for efficient virus replication

Shuai Cao1, Xiaoling Liu, Maorong Yu

  • 1Center for Molecular Virology, CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.

Journal of Virology
|February 21, 2012
PubMed

Insights

A newly identified nuclear export signal (NES) in influenza A virus matrix protein 1 (M1) is crucial for viral replication. This Flu-A-M1 NES facilitates M1 protein export, essential for efficient virus production.

Area of Science:

  • Virology
  • Molecular Biology
  • Cell Biology

Background:

  • The influenza A virus matrix protein 1 (M1) is vital for viral replication, assembly, and budding.
  • M1 protein shuttles between the cytoplasm and nucleus during the viral life cycle.

Purpose of the Study:

  • To identify and characterize a specific nuclear export signal (NES) for the influenza A virus M1 protein.
  • To elucidate the role of this NES in viral replication and M1 protein localization.

Main Methods:

  • Identification of a leucine-rich NES (Flu-A-M1 NES) conserved in influenza A virus subtypes.
  • Functional analysis using enhanced green fluorescent protein (EGFP)-NES fusion proteins in transfected cells.
  • Assessment of NES mutations in M1 protein localization and viral replication using rescued recombinant viruses.

Main Results:

  • The identified Flu-A-M1 NES specifically mediates nuclear export of M1 protein, demonstrated by EGFP-NES translocation.
  • Mutations in the Flu-A-M1 NES resulted in M1 nuclear retention and impaired viral replication, significantly reducing virus titers.
  • NES-defective M1 protein hindered nuclear export of viral RNPs (vRNPs) during infection.

Conclusions:

  • Nuclear export of influenza A virus M1 protein is specifically dependent on the Flu-A-M1 NES.
  • The Flu-A-M1 NES is critical for efficient influenza A virus replication and M1 protein function.

More Related Videos

Co-immunoprecipitation of the Mouse Mx1 Protein with the Influenza A Virus Nucleoprotein09:39

Co-immunoprecipitation of the Mouse Mx1 Protein with the Influenza A Virus Nucleoprotein

Published on: April 21, 2015

Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry09:38

Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry

Published on: June 26, 2019

Related Concept Videos

Nuclear Export01:42

Nuclear Export

The nucleus restricts several proteins within and allows others to pass. The restricted proteins possess a nuclear retention sequence or NRS, anchoring them to the nuclear lamins and preventing their transport to the cytosol. The non-restricted proteins, after their synthesis, are transported to their site of action, such as the cytosol or other organelles, with the help of nuclear export signals or NES.
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
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...
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...
Nuclear Localization Signals and Import01:46

Nuclear Localization Signals and Import

Proteins targeted to the nucleus carry short stretches of amino acid sequences called the nuclear localization signal or NLS. Classical nuclear localization signals are of two types: monopartite and bipartite NLS. Monopartite classical NLS (cNLS) consists of a single cluster of 4-8 amino acids. Bipartite cNLS consists of two clusters of  2-3 amino acids and a 9-12 residue long proline-rich linker bridging the two clusters. Signal clusters are rich in positively charged amino acids such as...
Nuclear Export of mRNA02:31

Nuclear Export of mRNA

Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
Nuclear Export of mRNA02:31

Nuclear Export of mRNA

Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...