A bacterial one-hybrid selection system for interrogating zinc finger-DNA interactions.
We have developed two bacterial one-hybrid systems for interrogating and selecting zinc finger-DNA interactions. Our systems utilize two plasmids: a zinc finger-plasmid containing the gene for the zinc finger fused to a fragment of the alpha subunit of RNA polymerase and a reporter plasmid where the zinc finger-binding site is located upstream of a reporter gene-either the gene encoding the green fluorescent protein (GFP) or chloramphenicol acetyltransferase (CAT). Binding of the zinc finger domain to the target binding site results in a 10-fold increase in chloramphenicol resistance with the CAT reporter and an 8- to 22-fold increase in total cell fluorescence with the GFP reporter. The CAT reporter allows for sequence specific zinc fingers to be isolated in a single selection step whereas the GFP reporter enables quantitative evaluation of libraries using flow cytometry and theoretically allows for both negative and positive selection. Both systems have been used to select for zinc fingers that have affinity for the motif 5'-GGGGCAGAA-3' from a library of approximately 2 x 10(5) variants. The systems have been engineered to report on zinc finger-DNA binding with dissociation constants less than about 1 microM in order to be most applicable for evaluating binding specificity in an in vivo setting.
Durai
Sundar
S
Department of Chemical and Biomolecular Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA.
Bosley
Allen
A
Abulencia
Alice Bridgeman
AB
Chandrasegaran
Srinivasan
S
Ostermeier
Marc
M
D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000737:chemistry*; D017930:Genes, Reporter; D008969:Molecular Sequence Data; D010957:Plasmids; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping; D016335:Zinc Fingers / Q000235:genetics*
D011994:Recombinant Proteins; D004247:DNA