The most efficient and widely used methods for transforming animal cells rely on liposomes or viral vectors. Viral vectors (lentivirus, AAV, adenovirus) achieve 80-95% efficiency with stable integration, while lipofection delivers plasmid DNA via cationic lipid vesicles for transient/high-throughput transfection in cultured mammalian cells.

Option Analysis

• (1) BAC: Bacterial artificial chromosomes clone large DNA inserts (>100 kb) in E. coli; inefficient for animal cell delivery due to size and bacterial origin.

• (2) Liposomes or viral vectors: Correct—liposomes (Lipofectamine) for transient expression (70-90% HEK293); viral vectors for stable lines/gene therapy (AAV: non-integrating, safe).​

• (3) Plasmids: DNA vectors used with transfection reagents, but bare plasmids alone have <1% efficiency without delivery method (liposomes/electroporation).

• (4) Agrobacterium tumefaciens: Plant-specific T-DNA transfer via Vir proteins; fails in animal cells lacking β-expansin receptors.

Answer: (2) Liposomes or viral vectors.​

Introduction to Animal Cell Transformation

The most efficient and widely used methods for transforming animal cells rely on liposomes or viral vectors. These deliver foreign DNA into mammalian cells for gene function studies, CRISPR editing, and gene therapy, achieving efficiencies unattainable by direct plasmid uptake.​

Viral Vector Superiority

• Lentivirus: Integrates into genome (MOI 1-10, 90%+ stable lines)

• AAV: Non-pathogenic, long-term episomal expression (retina/liver trials)

• Adenovirus: High titer transient expression (vaccines)

Liposome Chemical Transfection

Cationic lipids (DOTAP, Lipofectamine 3000) form lipoplexes with anionic DNA:

Efficiency: 50-90% (HEK293/HeLa); 10-30% primary cells.​

Why Other Methods Fail

GATE Biotechnology Application

Tests delivery system specificity: plants=Agrobacterium, animals=liposomes/virus. Essential for transgenics, gene therapy, cell line engineering questions.​