FIG. 1.

The lexA-Ume3p in vivo recruitment assay. lexA-Ume3p recruitment of the RNA polymerase holoenzyme is indicated by activation of a lexA_op-LEU2 reporter gene and growth of RSY472 on medium lacking leucine at 30°C (top panel). Cells harboring either Ume3p or lexA alone are unable to grow. At 37°C (bottom panel), lexA-Ume3p is no longer able to support growth due to the heat-induced destruction of the fusion protein. The positive control, lexA fused to the Ga14p activation domain, demonstrates that this system is not inherently temperature sensitive.