Figure 3.

Screening of interacting proteins with the bacterial two-hybrid system. DHP1 cells were cotransformed with a mixture of plasmids pTI8, pT18-zip, and pT18-Tyr and either pT25 (A) or pT25-zip (B), plated on LB–X-gal agar plates containing 0.5 mM isopropyl-β-d-thiogalactopyranoside, ampicillin, and chloramphenicol, and incubated for 30 hr at 30°C. Note that the cya⁺ colonies are larger than the cya ones.