FIG. 3.

Mhy1p binds specifically in vitro to the putative STRE pentanucleotide AGGGG. Mhy1p was translated in vitro, incubated with a radiolabeled probe which is derived from the upstream region of the CDC42 gene and which contains two copies of the AGGGG pentanucleotide, and analyzed by EMSA. The specificity of the DNA-protein interaction was determined by competition analysis with unlabeled probe and by EMSA with a mutant probe containing single-base mutations (AGGGG to TGGGG) in the two putative STREs of the wild-type probe. Lane 1, wild-type probe incubated with unprogrammed lysate. Lane 2, wild-type probe incubated with in vitro-translated Mhy1p. Lanes 3 to 6, wild-type probe incubated with in vitro-translated Mhy1p and 10-, 50-, 100-, and 500-fold molar excesses of unlabeled wild-type oligonucleotide, respectively. Lane 7, mutant probe incubated with in vitro-translated Mhy1p.