Lentiviral transfer plasmid verification is a critical quality control step to ensure the integrity of the genetic payload before viral production. Since these plasmids contain repetitive sequences and are prone to recombination, rigorous testing is essential.

Key Verification Steps

• Restriction Digest Analysis: High-resolution mapping confirms the correct backbone and insert size. Crucially, specific enzymes are used to verify the Long Terminal Repeats (LTRs), which are susceptible to deletions in standard E. coli strains.
• Sanger Sequencing: Targeted sequencing validates the promoter, the Gene of Interest (GOI), and junction sites to ensure no point mutations or frame shifts occurred during cloning.
• Diagnostic PCR: Used for rapid screening of colonies to confirm the presence and orientation of the insert.
• Full Plasmid Sequencing (NGS): Increasingly, Whole Plasmid Sequencing (WPS) is used to guarantee the entire construct, including regulatory elements, is intact.

Why It Matters

Failure to verify can lead to low viral titers, truncated transgene expression, or complete experimental failure. Using recombination-deficient bacteria (e.g., Stbl3 or CopyCutter) during preparation helps maintain plasmid stability.