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Sanger Sequencing Confirmation of GOI and Flanking Regions in Preclinical AAV Plasmids

PROVEN INTELLIGENCE ACCELERATING NEXT-GENERATION THERAPIES

Sanger Sequencing Confirmation of GOI and Flanking Regions in Preclinical AAV Plasmids

Sanger Sequencing for AAV Plasmid GOI Confirmation

CELL & GENE | RNA | BIOLOGICS

A scientist in a modern lab analyzes colorful DNA sequencing data on a tablet.

** Verifying the Genetic Blueprint of Your AAV Therapeutic.

Executive Summary

Sanger sequencing is the definitive method for confirming the identity and integrity of the gene of interest (GOI) and its flanking regulatory regions within an AAV plasmid backbone. This targeted verification is performed prior to large-scale vector production to ensure the genetic material is 100% correct, preventing the generation of incorrect vectors and mitigating significant downstream risks in preclinical programs.

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Frequently Asked Questions

    Why is Sanger sequencing used for AAV plasmid confirmation?

    Its high accuracy for specific, targeted regions provides unambiguous, base-by-base confirmation of the expression cassette, including the promoter, GOI, and polyA signal. It is the gold standard for verifying these functionally important sequences.

    What regions of the AAV plasmid must be sequenced?

    Comprehensive verification covers the entire expression cassette. This includes the promoter, the full gene of interest, the polyadenylation signal, and the flanking inverted terminal repeats (ITRs), which are required for genome packaging and expression.

    When is this sequencing performed in the AAV production workflow?

    Sequencing is a mandatory quality control step conducted after plasmid amplification and purification. This confirmation occurs before the plasmid is used for transfection in adherent or suspension-based systems for vector production.

The integrity of plasmid DNA is a primary variable in AAV manufacturing. An error introduced during cloning or amplification: a single base-pair mutation in the gene of interest or a deletion in an ITR: can compromise the function of the final vector and invalidate an entire production run. Verifying the plasmid sequence is a primary control measure that ensures the intended genetic payload is precisely what moves forward into manufacturing.

At Franklin Biolabs, we utilize Sanger sequencing for this targeted verification. While other methods exist for broader genomic analysis, Sanger provides the required precision and efficiency for confirming the functionally active regions of a plasmid. This level of verification provides the high-fidelity genomic data necessary to de-risk a program before committing to the resources required for vector production. This initial step is part of building a robust CMC data package for an 18-24 month IND timeline.

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Confirming Functionally Active Regions

Verification extends beyond the GOI itself. The integrity of the flanking ITRs is equally important, as these sequences are required for viral genome replication, packaging into the capsid, and conversion to a stable episome in the target cell. These repetitive sequences can be susceptible to recombination and deletion during plasmid amplification in E. coli.

Scientific literature reinforces the need for this precision. Studies exploring the drivers of AAV transport across biological barriers (PMID: 30819613) or the determinants of tissue-specific transduction patterns (PMID: 21778099) demonstrate how vector components dictate biological outcomes. Ensuring the plasmid sequence is correct is the first step in achieving predictable vector performance in vivo.

Integrating Sequencing into a Scalable CMC Pathway

Ensuring plasmid integrity is the first step in a series of precise manufacturing controls. This sequence data becomes a permanent part of the batch record and a key component of the documentation package for regulatory submissions, establishing a clear, traceable line from the initial plasmid construct to the final vector product.

As one of our partners noted, this early-stage work is what enables progress: “The AAV vector which they manufactured laid a foundation for development of a gene therapy candidate which will enter soon preclinical studies…” This continuity and documentation are built from early-stage quality control checkpoints like plasmid sequencing.

Featured Resource: To explore how this step fits into the broader context of capsid engineering, scalability, and preclinical safety profiling, watch the full webinar, “Vector Ready: Where AAV projects begin and how they succeed.”

A scientist in a lab coat and gloves looks through a microscope in a laboratory setting, with a blue color overlay.

Technical Visualization: AAV Plasmid Sequencing Workflow

Scientific Process Diagram

This content is for informational purposes. For guidance specific to your therapeutic program, please contact our team for a consultation.

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