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Updated: Oct 9, 2026

Fluorescence-based Neuraminidase Inhibition Assay to Assess the Susceptibility of Influenza Viruses to The Neuraminidase Inhibitor Class of Antivirals
09:31

Fluorescence-based Neuraminidase Inhibition Assay to Assess the Susceptibility of Influenza Viruses to The Neuraminidase Inhibitor Class of Antivirals

Published on: April 15, 2017

Mode of interference of trisodium phosphonoformate (INN: foscarnet sodium), with influenza virus mRNA synthesis

S Stridh, R Datema

    Virology
    |May 1, 1984
    PubMed

    Insights

    Foscarnet noncompetitively inhibits influenza RNA polymerase, blocking mRNA elongation after the conserved sequence initiation. This antiviral mechanism affects viral RNA synthesis.

    Area of Science:

    • Virology
    • Molecular Biology
    • Biochemistry

    Background:

    • Foscarnet is known to inhibit influenza RNA polymerase.
    • The precise mechanism of foscarnet's inhibition requires further elucidation.

    Purpose of the Study:

    • To investigate the mode of inhibition of foscarnet on influenza RNA polymerase.
    • To analyze the effects of foscarnet on mRNA synthesis initiation and elongation.

    Main Methods:

    • Enzyme-kinetic procedures were employed.
    • Product analysis was conducted to determine inhibition patterns.

    Main Results:

    • Foscarnet exhibited noncompetitive inhibition against ATP, CTP, and UTP.
    • Mixed inhibition was observed with respect to GTP.
    • Foscarnet inhibited mRNA elongation but not initiation, specifically after the conserved 5' sequence.

    Conclusions:

    • Foscarnet acts as a mixed inhibitor of influenza RNA polymerase.
    • The drug blocks viral mRNA formation by inhibiting the elongation step.
    • This inhibition occurs post-initiation, after the synthesis of the conserved 12-nucleotide sequence.

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