Release-Independent Transcription from Covalently Cross-Linked Hierarchically Folded DNA Condensates

Area of Science:

• Biotechnology
• Gene Therapy
• Nanotechnology

Background:

• Gene delivery systems are crucial for gene therapy.
• Current nonviral methods often face challenges with efficiency and safety.
• DNA condensation is a key strategy to improve gene delivery.

Purpose of the Study:

• To develop a novel DNA condensate structure for enhanced gene expression.
• To evaluate the safety and efficacy of these DNA condensates in vitro and in vivo.
• To explore a genome-integration-free platform for gene therapy.

Main Methods:

• Ordered DNA condensates were assembled using a PEG-poly(l-lysine) block copolymer.
• Supercoiled plasmids were folded into anisotropic "nanoworms".
• Condensates were chemically cross-linked and tested for transcription and translation in vitro, and gene expression in live cells and animals.

Main Results:

• Nanoworm DNA condensates sustained sequence-specific transcription and translation efficiently.
• Gene expression from nanoworm condensates occurred without structural disassembly in cells and animals.
• Disordered DNA spheres (jetPEI) were transcriptionally silent.
• Nanoworm condensates demonstrated robust cytosolic expression, bypassing the need for DNA release.

Conclusions:

• Ordered DNA nanoworms are effective nonviral gene delivery vehicles.
• These crystalline DNA assemblies offer a safer gene therapy approach by preventing genome integration.
• The "uncoat-and-release" step is circumvented, reducing insertional mutagenesis risk.