FIG. 3.

Stimulation of HIS4 transcription by insertions of CCGNN repeats in the upstream regulatory region. Single yeast colonies were suspended in water, and 1:10 serial dilutions were performed. A 10-μl portion of each dilution was placed on solid medium, with the most concentrated suspension on the left side of the plates. Each row represents a different strain as follows: DNY26, wild-type HIS4 upstream regulatory sequences; PD81, homozygous for his4-Δ52 mutation which removes binding sites for all known HIS4 transcription activators; DTK273, homozygous for his4-C48; DTK347, homozygous for his4-C12; and DTK364, homozygous for his4-C12d.