Zinc finger motif is a novel DNA binding motif characterized by the unique role of zinc; the protein folding and the DNA binding ability are governed by the coordination of a zinc ion. In C2H2-type zinc finger, two cysteines and two histidines contribute to form a globular domain through zinc coordination. The zinc finger of C2H2-type gives promise of recognition for any DNA sequences because of its recognition mode. A C2H2-type zinc finger protein Sp1 has been converted into artificial site-specific nuclease with an attached Ni-based DNA cleavage unit (Gly-Gly-His). This protein cleaved DNA at a single site near the Sp1 recognition sequence. The zinc finger-based nuclease is applicable to chromosome mapping and sequencing.