Modified closed-ended dna (cedna)

ceDNA vectors having linear and continuous structure can be produced in high yields and used for effective transfer and expression of a transgene. ceDNA vectors comprise an expression cassette and two different ITR sequences derived from AAV genomes in a specified order. Some ceDNA vectors provided herein further comprise cis-regulatory elements and provide high gene expression efficiencies. Further provided herein are methods and cell lines for reliable and efficient production of the linear, continuous and capsid-free DNA vectors. In a specific embodiment the invention is non-viral capsid-free DNA vector with covalently-closed ends (ceDNA vector), wherein the ceDNA vector comprises at least one nucleotide sequence positioned between asymmetric inverted terminal repeats (asymmetric ITRs), wherein at least one of the asymmetric ITRs comprises a deletion of at least a D and D' ITR region, and in at least one of an A, A', B, B', C and/or C' ITR region, and wherein at least one of the asymmetric ITRs comprises a functional terminal resolution site and a Rep binding site, and wherein the ITRs are derived from an adeno associated virus (AAV).