A caged DNA template, which bears a caged thymine [4-O[2-(2-nitrophenyl)propyl]thymine, T-NPP} near its 5'-end, was prepared, and used for in vitro DNA replication. The photo labile 2-(2-nitrophenyl)propyl (NPP) group efficiently blocked DNA polymerase reaction, and site-selectively terminated the extension of complementary strand there. This NPP-group can be removed by simple 30-min UVA irradiation to the solution, to give restriction-enzyme-free sticky end on the template strand.