FIG. 1.
Two-hybrid analysis of the TCTP-Plk interaction. A Plk carboxy-terminal bait containing the polo box interacts with HeLa partial clones of TCTP in the two-hybrid screen. Five of the nine positives from the screen were partial clones of human TCTP. One partial human clone and full-length murine TCTP were shown to interact with full-length Plk but not full-length Snk, and this interaction was shown to be dependent on the polo box of Plk (f.s. is the frameshift mutation). Lamin and GBT9 (GAL4 DNA-binding domain vector) were used as negative controls. Interactions were determined by assaying for β-galactosidase activity, with interaction or activity strength denoted by dark, medium, light, and (--), which roughly correlated to turning blue in under 1 h, between 1 and 4 h, longer than 4 h, and not detectable after 24 h, respectively. The Plk bait showed a slight degree of autoactivation; however, the Plk-TCTP (both partial and full-length) interactions were consistently much stronger (detectably blue in 1.5 h versus 6 h for the control) as determined by β-galactosidase activity.