Figure 1.

Schematic representation of the system. The pG5luc vector contains five GAL4-DNA binding domains upstream of a minimal TATA box, which in turn is upstream of the firefly luciferase gene. Box A and B are the interacting partners in ACT and BIND construct, respectively. Box TA in the ACT construct is a transcriptional activation domain. (A) If the target gene contains a NLS, the ACT construct product can translocate into the nucleus and interact with the BIND construct product, which activates the luciferase reporter gene. (B) If the target gene does not contain any coding sequence for NLSs, then the ACT construct product can not enter the nucleus and the luciferase gene remains inactivated.