Enhancement of expression of a single-stranded, heterologous nucleotide sequence from recombinant viral vectors by designing the sequence such that it forms intrastrand base pairs

The present invention provides a recombinant adeno-associated virus (rAAV) virus preparation, which rAAV virus preparation is essentially free of other viruses, comprising an rAAV vector, wherein the rAAV vector comprises a single-stranded heterologous nucleotide sequence comprising a coding region which forms intrastrand base pairs such that expression of the coding region of the heterologous sequence is enhanced relative to an rAAV vector that lacks sufficient intrastrand base pairing to enhance said expression, wherein the rAAV vector comprises one or more inverted terminal repeat (ITR) sequences flanking said heterologous sequence, wherein the rAAV vector is less than 2.5 kilobases in length, wherein the total amount of unique sequence present in the heterologous sequence is about one-half of the heterologous sequence and wherein the heterologous sequence forms intrastrand base pairs along most or all of its length, for use in a method of treatment of the human or animalbody by therapy.