Figure 1.

PIN*POINT strategy. (a) A diagram of the structure of FokI endonuclease showing the DNA sequence-specific and nuclease domains. (b) The expression vector for Sp1 pointer is cotransfected with a target plasmid that contains the Sp1 binding site into MEL cells. The crescent portion of Sp1 (middle of the diagram) represents the DNA binding domain of Sp1. The flexible linker region and the nuclease domain are represented as a string and an arrowhead, respectively. Low molecular weight DNA is recovered and cleavage in the promoter of the target plasmid is detected by primer extension with a radioactively labeled internal primer (∗). For increased sensitivity, ligation-mediated PCR (LM-PCR) may also be used.