described herein are constructions of recombinant dna comprising modified adeno - associated virus dna sequences capable of functioning as a eukaryotic expression vector for expressing foreign dna sequences using a novel transcription promoter comprising the termini of aav dna . it is shown that expression of a test reporter gene can be obtained from this vector in mammalian cells . it is further shown that this combination of vector and promoter can be used to introduce and express a human gene and correct a genetic defect in human cells resulting from malfunction of the mutant endogenous gene . further , the vector can be used to correct the genetic defect by expressing a modified version of the human gene consisting of a fusion of part of the said gene and a synthetic sequence contained in the vector .