Some time ago, we have detected a 11 bp-deletion within the 5'-ITR of numerous AAV plasmids. Currently, other scientists reported that they have observed the same mutation in their plasmids. It is currently unclear, whether and how this deletion affects viral vector production. We have therefore decided not to work with AAV plasmids having a defective 5'-ITR.
As most of the the AAV plasmids available today go back to psub-201, we have developed a rescue strategy based on psub-201 that allows the replacement of the mutated 5'-ITR.
For more detailed information on the 11 bp-deletion and the rescue strategy, please have a look in FAQ-Plasmids and Cloning.