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Characterization of a nuclear localization signal in the foot-and-mouth disease virus polymerase

Maria Teresa Sanchez-Aparicio1, Maria Flora Rosas, Francisco Sobrino

  • 1Centro de Biología Molecular, "Severo Ochoa" (CSIC-UAM), Cantoblanco 28049, Madrid, Spain.

Virology
|July 27, 2013
PubMed

Insights

The MRKTKLAPT sequence in Foot-and-Mouth Disease Virus (FMDV) 3D protein acts as a nuclear localization signal (NLS). Mutations in key residues essential for virus multiplication indicate their importance for viral replication.

Area of Science:

  • Virology
  • Molecular Biology
  • Cell Biology

Background:

  • Foot-and-Mouth Disease Virus (FMDV) is a significant pathogen affecting livestock.
  • Understanding viral protein function, including intracellular localization, is crucial for developing control strategies.

Purpose of the Study:

  • To investigate if the MRKTKLAPT sequence (residues 16-24) in FMDV 3D protein functions as a nuclear localization signal (NLS).
  • To determine the role of specific residues within this sequence in viral replication.

Main Methods:

  • Site-directed mutagenesis was used to create K18E and K20E mutants in the FMDV 3D protein.
  • Transient expression assays were performed with wild-type and mutant 3D and 3CD proteins.
  • Green fluorescence protein (GFP) fusion constructs were utilized to assess nuclear localization.
  • Full-length FMDV RNA with introduced mutations was used to generate viruses.

Main Results:

  • Mutations K18E and K20E in the 3D protein and its precursor 3CD resulted in decreased nuclear localization.
  • Fusion of the MRKTKLAPT sequence to GFP enhanced its nuclear localization, an effect abolished by mutations.
  • Revertant FMDV viruses with K18 and K20 lysines were produced, replacing the introduced glutamate mutations.
  • The presence of lysines at positions 18 and 20 of 3D is essential for FMDV multiplication.

Conclusions:

  • The MRKTKLAPT sequence in FMDV 3D protein functions as a nuclear localization signal (NLS).
  • Lysine residues at positions 18 and 20 within this NLS are critical for FMDV replication and viral multiplication.
Keywords:
FMDVNLSViral polymerase

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