Methods of using randomized libraries of zinc finger proteins for the identification of gene function

A method of identifying a gene or genes associated with a selected phenotype, the method comprising the steps of:

• (a) providing a nucleic acid library comprising nucleotide sequences that encode at least partially randomized zinc finger proteins;
• (b) transducing cells with expression vectors, each comprising a nucleotide sequence from the library;
• (c) culturing the cells so that zinc finger proteins are expressed in the cells, wherein the zinc finger proteins modulate gene expression in at least some of the cells;
• (d) assaying the cells for a selected phenotype and determining whether or not the cells exhibit the selected phenotype;
• and
• (e) identifying, in cells that exhibit the selected phenotype, the gene or genes whose expression is modulated by expression of a zinc finger protein, wherein the gene so identified is associated with the selected phenotype.