STRUCTURE-BASED DESIGN OF TRANSCRIPTION FACTORS

Computer modeling suggested that transcription factors with novel sequ ence specificities could be designed by combining known DNA binding do mains. This structure-based strategy was tested by construction of a f usion protein, ZFHD1,that contained zinc fingers 1 and 2 from Zif268, a short polypeptide linker, and the homeodomain from Oct-1. The fusion protein bound optimally to a sequence containing adjacent homeodomain (TA-ATTA) and zinc finger (NGGGNG) subsites. When fused to an activat ion domain, ZFHD1 regulated promoter activity in vivo in a sequence-sp ecific manner. Analysis of known protein-DNA complexes suggests that m any other DNA binding proteins could be designed in a similar fashion.