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Defective segment 1 RNAs that interfere with production of infectious influenza A virus require at least 150

S D Duhaut1, N J Dimmock1

  • 1Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK1.

The Journal of General Virology
|January 25, 2002
PubMed

Insights

A critical length of the 5' end sequence in defective influenza A virus RNAs is essential for their ability to interfere with virus multiplication. This finding highlights a vital role for this sequence in the virus life cycle.

Area of Science:

  • Virology
  • Molecular Biology

Background:

  • Naturally occurring defective influenza A virus RNAs possess specific 5' and 3' end sequences.
  • The 5' end sequence is typically around 200 nucleotides (nt), while the 3' end can be as short as 25 nt.
  • Defective RNA stability during serial passage is influenced by the length of the 5' end sequence.

Purpose of the Study:

  • To investigate the influence of 5' end sequences of defective segment 1 RNAs on their interference with infectious influenza A virus multiplication.
  • To determine the minimum and optimal lengths of the 5' end sequence required for effective interference.

Main Methods:

  • Studied six defective segment 1 RNAs from H3N8 and H7N7 influenza viruses.
  • Transfected defective RNAs into cells and assessed their interference with plasmid-produced infectious A/WSN virus (H1N1).
  • Analyzed the concentration-dependent interference and its correlation with defective RNA length and intracellular presence.

Main Results:

  • Transfected defective RNAs interfered with infectious virus production in a concentration-dependent manner.
  • The extent of interference was directly dependent on the length of the 5' end sequence, requiring at least 150 nt and maximal at 220 nt.
  • Reduced virus multiplication correlated with detectable intracellular defective RNA and inverse packaging of defective versus full-length segment 1 RNA.

Conclusions:

  • A critical length of the 5' end sequence is essential for the interfering properties of defective influenza virus RNAs.
  • This specific 5' end sequence length plays a vital role in the influenza virus life cycle, potentially by affecting RNA packaging and infectivity.

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