A recombinant vector comprising a polynucleotide containing a cis-acting central initiation region (cPPT) and a cis-acting termination region (CTS) is disclosed. These regions are of retroviral or retroviral-like origin. The vector further comprises a defined nucleotide sequence (transgene or sequence of interest) and regulatory signals for reverse transcription, expression, and packaging, wherein the regulatory signals are of retroviral or retroviral-like origin. In some embodiments the vector is incorporated into compositions for therapeutic purposes. In other embodiments the vector is incorporated into immunogenic compositions, The vector is also useful for methods such as ex vivo transfection or ex vivo transduction of non-mitotic differentiated cells.