FIG. 2.

Comparison of DNA binding by ZEBRA and Z(S186A) by competition EMSA. The oligonucleotide probe contained an AP-1 heptamer site (A) or the ZRE-R site (B). In panel A, 1 U of ZEBRA and Z(S186A) was determined to be that amount of bacterial extract that contained an approximately equivalent amount of immunoreactive ZEBRA or mutant protein; in panel B, the volume of cell extract required to achieve equivalent immunoreactivity is indicated. The binding of ZEBRA and Z(S186A) was assessed alone or in the presence of increasing amounts of competitor ZΔ131 extract. The proportion of probe that was bound by each protein was quantitated by phosphorimage analysis and is indicated below the gel.