Activation of HIV-specific ribozyme activity by self-cleavage

Area of Science:

• Molecular Biology
• Virology
• Biochemistry

Background:

• Hammerhead ribozymes are RNA molecules with catalytic activity.
• Targeting Human Immunodeficiency Virus type 1 (HIV-1) RNA is a strategy for antiviral therapy.
• Previous attempts to express active ribozymes in eukaryotic vectors faced challenges.

Purpose of the Study:

• To design and test a hammerhead ribozyme for in trans cleavage of HIV-1 RNA.
• To overcome limitations of cis-acting inhibitory sequences in ribozyme expression.
• To achieve effective cleavage of target HIV-1 RNA sequences.

Main Methods:

• A hammerhead ribozyme targeting the R region of HIV-1 RNA was engineered into a eukaryotic expression vector.
• In vitro studies were conducted using T3 RNA polymerase and specific target sequences.
• A self-cleavable ribozyme system was developed by inserting the target sequence upstream of the ribozyme coding sequence.

Main Results:

• The initial ribozyme construct showed no activity against the target HIV-1 RNA.
• The modified self-cleavable ribozyme successfully released an active catalytic domain via cis cleavage.
• The released ribozyme demonstrated in vitro activity at 37°C against multiple HIV-1 RNA transcripts.

Conclusions:

• A self-cleavable hammerhead ribozyme system can overcome expression challenges and achieve specific cleavage of HIV-1 RNA.
• This approach enhances ribozyme activity for potential therapeutic applications against HIV-1.
• The strategy of cis cleavage for trans activity offers a viable method for functional ribozyme expression.