USA (Transatlantic Today) – Researchers from Kanazawa University, IMDEA Nanoscience, and CNB-CSIC have made significant strides in understanding the RNA synthesis process of Influenza A. Their experiments, reported in ACS Nano, uncover a series of conformational stages that the virus’s recombinant genomes undergo during replication.
Influenza A, known for causing severe local epidemics and pandemics, has driven scientists to explore its replication mechanisms intensively. The international team, led by Shingo Fukuda, Jaime Martin-Benito, and Borja Ibarra, utilized high-speed atomic force microscopy and electron microscopy to observe the conformational dynamics of recombinant viral genomes (rRNPs) during RNA synthesis.
Overcoming Structural Challenges
Previous research efforts were stymied by the bulky double-helical structure of viral ribonucleoproteins (vRNPs), which obscured detailed observation. To address this, the researchers created a circular recombinant ribonucleoprotein complex (rRNP), facilitating real-time tracking of individual rRNP complexes during RNA synthesis through HS-AFM.
According to Phys.org, the study provides the first direct experimental evidence that individual rRNPs can be reused for multiple cycles of transcription and replication—a crucial feature for viral multiplication. Additionally, it highlights how the stability of secondary structures in nascent RNA impacts the rate of RNA synthesis.
The researchers conclude that their approach is valuable for investigating viral transcription and replication mechanisms. They note, “Transcriptional pausing is an intrinsic property of most RNA polymerases, and its regulation is central to gene expression control.” Future single-molecule experiments on real-time RNA synthesis kinetics by the influenza A virus RNA-dependent RNA polymerase (IAV RdRp) within the RNP context will further elucidate the nature and roles of potential pause states in viral transcription and replication.
