The invention concerns a recombinant vector characterised in that it
comprises a polynucleotide comprising a central initiation cis-active
region (cPPT) and a termination cis-active region (CTS), said regions
being of retroviral or retroviral-like origin, said vector further
comprising a predetermined nucleotide sequence (transgene or nucleotide
sequence of interest) and retranscription regulating, expressing and
packaging signals of retroviral or retroviral-like origin.