Characterizing protein-nucleic acid interactions with challenge phages

Abstract

Challenge phages are modified versions of bacteriophage P22 that are designed to study protein-nucleic acid interactions in vivo using the phage ant gene as a reporter. ant encodes a regulator of the lysogenic response, and its activity can be easily and sensitively monitored. P22 challenge phages can be used to characterize many different sequence-specific protein-DNA interactions by constructing derivatives that contain DNA binding sites of interest. The foreign DNA binding site is substituted for the phage O mnt operator, which controls ant transcription. In addition, challenge phages can be constructed to characterize protein-RNA interactions by substituting DNA encoding the appropriate RNA binding site upstream of the translation start of the ant gene. Specific applications of challenge phages will be discussed.