Structure of genes coding the envelope proteins of the avian influenza a virus and bovine leucosis virus

This paper comparatively analyzes the density of nucleotide sequences potentially predisposed to the formation of noncanonical DNA structures (G4 quadruplexes) on the hemagglutinin (HA) and neuraminidase (NA) genes of the avian influenza A virus (H5N1) and the env and pol genes of the bovine leucosis virus. The higher genetic heterogeneity of the HA gene in comparison with the NA gene coincided with the high frequency of the nucleotide sequences predisposed to the formation of G4 quadruplexes. The same tendency was observed when comparing the distribution of potential G4 quadruplexes in the env and pol genes of the bovine leucosis virus. We discuss a possible relation between the increased density of the noncanonical DNA structures in the genes whose products interact with the receptor system of target cells of a retrovirus infection and their genetic heterogeneity maintained in the host-pathogen system.