FIG. 1.

Schematic diagram of the ARS plasmids used in the DpnI assay. The A and B elements are shown by boxes. A cross represents the linker substitution of each element. In the B3/Gal4 and B3/LexA plasmids, the B3 element was replaced by the Gal4 and LexA binding sequence, respectively. In the mB3 plasmid, point mutations were introduced into the consensus sequence of the Abf1p binding site as described in Marahrens and Stillman (30). Each fragment containing an ARS was inserted into pSK⁺ as described in Materials and Methods.