AAV Cassette Packaging Budget

Audit a component-level AAV cassette budget, including ITRs if present; caller supplies the applicable genome capacity.

Description

Sum AAV cassette component lengths and compare the total with a supplied genome-size budget.

A recombinant adeno-associated virus cassette contains more than its transgene: regulatory sequence and inverted terminal repeats also contribute to the genome intended for packaging. Genome size affects vector packaging, and experimental outcomes cannot be reduced to a universal pass/fail length.^[1]

This calculator provides a bookkeeping budget. You supply component names, component lengths in bases, and a maximum genome length. It sums the lengths and reports both remaining capacity and whether the total is at or below that maximum.

The maximum is your design constraint, not a built-in biological guarantee. Include each intended packaged sequence once, including both terminal repeats where applicable; omitted or overlapping components distort the arithmetic.

When to use AAV Cassette Packaging Budget

Use it to compare candidate cassette designs or reconcile component lengths against a documented project-specific budget before sequence and experimental review.

How to use AAV Cassette Packaging Budget and interpret its calculation

Enter aligned, nonempty componentNames and componentLengthsBp lists with unique names and nonnegative integer lengths.
Enter a positive integer maximumGenomeBp chosen for the design context.
Run the sum and read totalGenomeBp, remainingCapacityBp, and withinPackagingBudget. A negative remaining capacity states how many bases exceed the supplied budget.

total = Σ component lengths; remaining = maximum − total; within budget = total ≤ maximum

The comparison includes equality and preserves negative remaining capacity.

Lengths and the maximum must be safe integers, and the sum must remain a safe integer. Zero-length components are allowed. Names identify entries but do not trigger any sequence-specific calculation.

json

{
  "input": {
    "componentNames": [
      "ITRs",
      "promoter",
      "transgene"
    ],
    "componentLengthsBp": [
      290,
      500,
      3500
    ],
    "maximumGenomeBp": 4700
  },
  "output": {
    "totalGenomeBp": 4290,
    "remainingCapacityBp": 410,
    "withinPackagingBudget": true
  }
}

Budget relation	Output
Total equals maximum	Remaining zero; within budget true.
Total exceeds maximum by 100 bases	Remaining −100; within budget false.
All listed lengths zero	Total zero; all of the supplied budget remains.

Limitations and assumptions

It does not inspect sequence, verify terminal repeats, identify unintended backbone sequence, or adjust for vector configuration. Budget arithmetic alone does not predict packaged-genome integrity, yield, expression, transduction, or potency.

Different designs and production systems may require different constraints. The example maximum must not be treated as a universal capacity or a release specification.

Alternative or Complementary methods

Confirm the intended packaged genome from the assembled sequence, then review design-specific packaging evidence. Coordinate-based retention or deletion summaries can answer structural questions that a component sum cannot.

References

Effect of Genome Size on AAV Vector Packaging (Wu, Yang, and Colosi, 2010) — Molecular Therapy

Similar or alternative tools

Retained Packaging Signal Interval
Check retention of a supplied packaging-signal interval.
Defective Genome Deletion Union
Count retained length after merging supplied deletion annotations.