Abstract: A methodology that allows for highly efficient transfer and stable integration of DNA into both established eukaryotic cell lines and primary cells, including non-dividing cells such as human peripheral blood monocytes and macrophages, entails the use of a synthetic polypeptide comprised of a peptide domain which corresponds to a nuclear localization signal sequence and a DNA binding domain which is rich in basic amino acids, separated by a hinge region of neutral acid which prevents stearic interference between the two domains. A synthetic polypeptide that allows for highly efficient transfer of DNA into eukaryotic cells, including, for example, non-dividing cells such as human peripheral blood monocytes and macrophages.