Nuclease resistant ribozymes with high catalytic activity

Area of Science:

• Biochemistry
• Molecular Biology
• Synthetic Biology

Background:

• Hammerhead ribozymes are RNA enzymes with conserved structures crucial for catalysis.
• The role of the ribose-phosphate backbone in hammerhead ribozyme function is not fully understood.
• DNA analogs with similar sequences lack catalytic activity, highlighting backbone importance.

Purpose of the Study:

• To investigate the impact of modified ribonucleotides on hammerhead ribozyme activity and stability.
• To identify critical positions within the ribozyme backbone essential for catalysis.
• To develop robust artificial ribozymes for potential therapeutic and research applications.

Main Methods:

• Synthesis of artificial ribozymes using modified ribonucleotides (2'-O-allyl and 2'-O-methyl).
• Systematic analysis of partially substituted polymers to determine essential modification sites.
• Characterization of catalytic activity and stability of fully substituted ribozymes.

Main Results:

• A minimum of six non-contiguous positions were identified where modifications significantly affect activity.
• Ribozymes with modifications at these six positions, but otherwise fully substituted, retained high catalytic activity.
• These artificial ribozymes demonstrated efficient trans-cleavage of target RNAs in a sequence-specific manner.

Conclusions:

• The ribose-phosphate backbone plays a critical role in hammerhead ribozyme catalysis.
• Artificial ribozymes with specific backbone modifications exhibit enhanced stability against nuclease degradation and serum.
• These engineered ribozymes show promise for in vivo gene expression modulation and therapeutic interventions.