FIG. 3.

Comparison of DNA binding activities by ZEBRA and a group of Z(S186) mutant proteins. (A) Bacterial lysates containing ZEBRA or Z(S186) mutant proteins were examined by immunoblotting with rabbit antiserum to ZEBRA. The level of expressed protein was quantitated by phosphorimagery and adjusted so that all DNA binding reactions contained approximately equal amounts of immunoreactive protein. (B) EMSAs of ZEBRA and Z(S186) mutant proteins with duplex oligonucleotide probes harboring one of several known ZEBRA binding sites labeled with polynucleotide kinase. Lane 6 contained extract of bacterial cells transformed with the vector pET-11d; lane 7 contained extract of E. coli BL21(DE3) cells alone. Only the portion of the gel containing probe that was shifted by the protein is shown.