Large BACs transfect more efficiently in circular topology

Area of Science:

• Molecular Biology
• Genetics
• Biotechnology

Background:

• DNA topology significantly impacts gene delivery efficiency in mammalian cells.
• Previous studies focused on small plasmids (<10 kb), leaving large DNA vectors largely unexamined.
• Large vectors carrying intact genomic DNA are crucial for studying complex genetic elements.

Purpose of the Study:

• To investigate the influence of DNA topology on the transfection efficiency of large DNA vectors (BACs) in mammalian cells.
• To compare the expression levels of circular versus linear BACs.
• To provide insights for optimizing gene delivery vector design.

Main Methods:

• Transfection of mammalian cells with circular and linear bacterial artificial chromosomes (BACs) of varying sizes (11 kb and 100 kb).
• Quantification of enhanced green fluorescent protein (eGFP) expression as a measure of transfection efficiency.
• Comparison of expression levels between circular and linear BAC constructs.

Main Results:

• Circular BACs demonstrated significantly higher transfection efficiency compared to linear BACs.
• eGFP expression was up to 3.1-fold higher for circular 11 kb BACs and 8.9-fold higher for circular 100 kb BACs.
• DNA topology is a critical factor for the efficient delivery and expression of large DNA constructs.

Conclusions:

• Circular DNA topology enhances the transfection efficiency of large bacterial artificial chromosomes (BACs) in mammalian cells.
• These findings are crucial for the development of advanced gene delivery systems and the study of large intact transgenes.
• Optimizing DNA vector conformation is key for efficient gene expression studies.