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PB1-F2 gene in influenza a viruses of different hemagglutinin subtype

H Pancuchárová1, G Russ

  • 1Institute of Virology, Slovak Academy of Sciences, Dúbravská cesta 9, 845-05 Bratislava, Slovak Republic.

Acta Virologica
|December 21, 2006
PubMed

Insights

Influenza A virus (IAV) PB1-F2 protein length varies among isolates. Truncated forms, lacking key functional regions, are found in some avian and human H1 subtype viruses.

Area of Science:

  • Virology
  • Molecular Biology
  • Genetics

Background:

  • The Influenza A virus (IAV) PB1 polymerase gene's +1 reading frame encodes the PB1-F2 protein.
  • The PR8 virus (H1N1) PB1-F2 is 87 amino acids (aa) long, but most IAV isolates can encode a 90-aa protein.

Purpose of the Study:

  • To analyze the sequence variability of the PB1-F2 protein across various Influenza A virus isolates.
  • To investigate the potential for truncated PB1-F2 variants and their implications.

Main Methods:

  • Analysis of nucleotide sequences from 626 IAV isolates from GenBank and the Influenza Sequence Database.
  • Comparative analysis of PB1-F2 protein lengths and conserved regions.

Main Results:

  • Most IAV isolates have the capacity to encode a 90-aa PB1-F2, with conservative variations in the extra three amino acids.
  • Some human, avian, and swine H1 subtype IAVs can encode C-terminally truncated PB1-F2 proteins.
  • Truncated PB1-F2 in H1 isolates lacks mitochondrial targeting and apoptosis-related regions.
  • Approximately 50% of avian H9 subtype isolates possess an open reading frame for truncated PB1-F2.
  • A 18-aa region (10 N-terminal, 8 C-terminal) is strictly conserved in all 148 analyzed human isolates.

Conclusions:

  • The PB1-F2 protein exhibits significant length variation across IAV strains.
  • Truncated PB1-F2 variants may have altered functions due to the loss of critical domains.
  • Conserved N-terminal and C-terminal regions suggest functional importance for PB1-F2.

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