INVERTED TERMINAL REPETITION IN ADENO-ASSOCIATED VIRUS-DNA - INDEPENDENCE OF THE ORIENTATION AT EITHER END OF THE GENOME

Complementary strands of adeno-associated virus DNA labeled with 32P at the 5'' ends were separated and then self-annealed to form single-stranded circles stabilized by H bonds between the complementary sequences in the inverted terminal repetitions. There are 2 distinct sequences in the terminal repetition which represent an inversion of the first 125 nucleotides (Lusby et al., Spear et al., 1977). Base pairing between terminal sequences of the same orientation leads to a normal double helical structure. If sequences of the opposite orientation pair, an aberrant secondary structure is formed. HpaII digestion of the self-annealed, single-stranded circles led to labeled terminal fragments that corresponded to those generated from termini of a normal double helical structure and those generated from an aberrant terminal secondary structure. Thus, the orientation of the terminal repetition at 1 end of the genome is not influenced by the orientation at the other end.