G-quadruplexes in H1N1 influenza genomes

BACKGROUND: Influenza viruses are dangerous pathogens.

Seventy-Seven genomes of recently emerged genotype 4 reassortant Eurasian avian-like H1N1 virus (G4-EA-H1N1) are currently available.

We investigated the presence and variation of potential G-quadruplex forming sequences (PQS), which can serve as targets for antiviral treatment.

RESULTS: PQS were identified in all 77 genomes.

The total number of PQS in G4-EA-H1N1 genomes was 571.

Interestingly, the number of PQS per genome in individual close relative viruses varied from 4 to 12.

PQS were not randomly distributed in the 8 segments of the G4-EA-H1N1 genome, the highest frequency of PQS being found in the NP segment (1.39 per 1000 nt), which is considered a potential target for antiviral therapy.

In contrast, no PQS was found in the NS segment.

Analyses of variability pointed the importance of some PQS; even if genome variation of influenza virus is extreme, the PQS with the highest G4Hunter score is the most conserved in all tested genomes.

G-quadruplex formation in vitro was experimentally confirmed using spectroscopic methods.

CONCLUSIONS: The results presented here hint several G-quadruplex-forming sequences in G4-EA-H1N1 genomes, that could provide good therapeutic targets.