We have explored the feasibility of using crude nuclear extracts and band-shift experiments, to select and clone short human DNA fragments that contain binding sites for sequence-specific nuclear proteins. We show that this strategy is feasible. It provides a means to systematically identify the recognition sequences of proteins found in nuclear extracts prepared from various tissues, in order to compile a protein-binding-sequence catalogue. A complete catalogue would provide the data needed for searching the "raw" human DNA sequences for occurrence of protein-binding sites and thus, to construct a statistical map of potential regulatory regions in the human genome.