Structural map of a microRNA-122: hepatitis C virus complex

Area of Science:

• Virology
• Molecular Biology
• RNA Biology

Background:

• MicroRNA-122 (miR-122) is a key host factor that enhances hepatitis C virus (HCV) replication.
• miR-122 is known to bind to the 5 -untranslated region (UTR) of the HCV genome.

Purpose of the Study:

• To investigate the detailed RNA secondary structure of the HCV 5 -UTR in the presence of miR-122.
• To elucidate the biophysical interactions between miR-122 and the HCV 5 -UTR.

Main Methods:

• Selective 2 -hydroxyl acylation analyzed by primer extension (SHAPE-MaP) was employed to map RNA structure.
• Analysis of RNA-RNA interactions between miR-122 and HCV 5 -UTR.

Main Results:

• Nearly all nucleotides of miR-122 participate in targeting the second binding site on the HCV 5 -UTR.
• These interactions extend beyond canonical seed base pairings, involving extensive 'tail' interactions.
• The observed interactions significantly enhance viral replication in cell culture.

Conclusions:

• The study reveals a complex structural interaction between miR-122 and the HCV 5 -UTR.
• Extensive non-canonical base-pairing interactions involving the miR-122 'tail' are crucial for enhancing HCV replication.
• This biophysical characterization provides new insights into host-pathogen interactions in HCV infection.