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Technical Report

Nature Structural & Molecular Biology 16, 1195–1199 (1 November 2009) | doi:10.1038/nsmb.1677

Positive selection of DNA-protein interactions in mammalian cells through phenotypic coupling with retrovirus production

Ulrich Tschulena , Kenneth R Peterson , Beatriz Gonzalez , Halyna Fedosyuk & Carlos F Barbas

Through the shuffling of predefined modular zinc finger domains with predictable target site recognition in vitro, we have generated a large repertoire of artificial transcription factors with five zinc finger domains (TFZFs). Here we report an effective strategy for the selection of ATF libraries by coupling expression of transcriptional activators of the promoter of interest to the enhanced production of retroviral vector particles transferring the TFZF encoding gene. Using this strategy, we successfully selected specific TFZFs that upregulate the expression of the γ-globin promoter. Selected transcription factors induced the expression of γ-globin when coupled to an activation domain and reduced expression when linked to a repression domain. This new retroviral approach might be used to select other TFZFs but might also be generalized for the selection of other protein and small-molecule interactions.