The T1α promoter mediates plasmid nuclear import in ATI cells. Plasmids (0.5 mg ml−1) carrying the promoter regions of T1α, AQP-5, caveolin-1, SP-C, SV40 DTS or no DTS were labeled with Cy3-PNA and cytoplasmically microinjected into both D5 primary ATI cells or R3/1 cells. After 5 h, the cellular localization of the plasmids was analyzed by fluorescence microscopy.