Coordinated Evolution of Influenza A Surface Proteins.

Area of Science:

• Virology
• Evolutionary Biology
• Genomics

Background:

• Influenza A virus surface proteins hemagglutinin (HA) and neuraminidase (NA) are key targets for immune responses and antiviral drugs.
• These proteins are physiologically interlinked, suggesting potential co-evolutionary dynamics.
• The extent of genetic interactions (epistasis) between HA and NA evolution remains largely unknown.

Purpose of the Study:

• To develop a novel phylogenetic method for detecting inter-gene epistasis between mutations in different genes.
• To investigate the coordinated evolution of influenza A virus surface proteins HA and NA.
• To understand how mutations in one surface protein affect the adaptive landscape of the other.

Main Methods:

• Development of a novel phylogenetic method to detect signatures of inter-gene epistasis.
• Application of the method to analyze co-evolutionary patterns between HA and NA mutations in influenza A virus.
• Phylogenetic analysis of viral genomic sequences.

Main Results:

• Influenza surface proteins HA and NA demonstrate coordinated evolution, with mutations in one protein affecting the spread of mutations in the other.
• Significant inter-gene epistasis was detected at numerous sites between HA and NA.
• Oseltamivir-resistance mutations in NA (H1N1) appear to have been facilitated by prior mutations in HA.

Conclusions:

• The adaptive landscape of viral proteins is highly sensitive to genomic context.
• Evolution of individual viral proteins should be considered within the framework of the entire evolving viral genome.
• Co-evolutionary dynamics between HA and NA play a significant role in influenza virus adaptation and antiviral resistance.