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Updated: Jul 16, 2026
Production and Titering of Recombinant Adeno-associated Viral Vectors
Published on: November 27, 2011
Viral serotype and the transgene sequence influence overlapping adeno-associated viral (AAV) vector-mediated gene
Arkasubhra Ghosh1, Yongping Yue, Dongsheng Duan
1Department of Molecular Microbiology and Immunology, The University of Missouri, School of Medicine, Columbia, MO 65212, USA.
Background:
The overlapping approach was developed recently to expand the adeno-associated viral (AAV) packaging capacity. In this approach, a gene is split into two partially overlapping fragments and separately packaged into an upstream and a downstream vector, respectively. Transgene expression is achieved in co-infected cells after homologous recombination. Despite the promising proof-of-principle results in the lung, the efficiency has been very disappointing in skeletal muscle. Here we examined two potential rate-limiting factors including AAV serotype and the transgene sequence.
Methods:
To study serotype effect, we delivered AAV-2, -5 and -6 overlapping vectors (5 x 10(8) vg particles of the upstream and the downstream vectors, respectively) and 5 x 10(8) vg particles of the intact gene vector to the tibialis anterior muscles of 7-week-old C57Bl/6 mice, respectively. To determine the effect of transgene sequence, we compared LacZ and alkaline phosphatase (AP) overlapping vectors. Transduction efficiency was quantified 6 weeks later by scoring the percentage of transgene-positive myofibers.
Results:
AAV-2 overlapping vectors barely resulted in detectable transduction. Transduction efficiency was significantly improved in AAV-5 and AAV-6. The highest level was achieved in AAV-6 that reached 42% and 96% of that of the intact gene vector for the LacZ gene and the AP gene, respectively. Surprisingly, AAV-6 overlapping vector resulted in higher transduction than did AAV-2 and AAV-5 intact gene vectors.
Conclusions:
Our findings suggest that AAV serotype and the transgene sequence play critical roles in the overlapping approach. AAV-6 holds great promise for overlapping vector-mediated muscle gene therapy.
