RNA self-cleavage activated by ultraviolet light-induced oxidation

Area of Science:

• Molecular Biology
• Virology
• Biochemistry

Background:

• Hepatitis C Virus (HCV) and Classic Swine Fever Virus (CSFV) possess highly structured 5'-genomic regions.
• Ribozyme activity, the ability of RNA to catalyze biochemical reactions, is crucial in understanding RNA's role in early life.

Purpose of the Study:

• To investigate a novel UV-C-light-induced ribozyme activity in HCV and CSFV.
• To characterize the cleavage sites, reaction products, and structural requirements for this activity.

Main Methods:

• Exposure of viral RNA to UV-C light to induce cleavage.
• Analysis of cleavage sites and reaction products using biochemical assays.
• Comparison of structural requirements for cleavage between HCV and CSFV RNA.

Main Results:

• A novel UV-C-light-dependent ribozyme activity was identified in the 5'-genomic regions of HCV and CSFV.
• Cleavage occurred selectively at specific nucleotide positions (HCV C79/U78 and CSFV A45/U44).
• The majority of products had 3'-phosphate and 5'-phosphate termini, indicating a specific cleavage mechanism.

Conclusions:

• The findings suggest the existence of previously unidentified UV-activated ribozymes in structured RNAs.
• The conserved nature of this activity across different viruses implies a potential role in early RNA evolution.
• Structural requirements for cleavage differ between HCV and CSFV, hinting at diverse evolutionary pathways for ribozymes.