The N-terminal NUP98 contains a transactivation domain. (A) Western blot analysis of GAL4 DNA binding domain fusion proteins that were expressed in transiently transfected HeLa cells. Fusion proteins were detected by using a monoclonal antibody directed against the GAL4 DNA binding domain. (B) Transfection assay of HeLa cells using the GAL4 luciferase reporter plasmid and expression plasmids encoding GAL4 fusion proteins (left panel). (C) Jurkat cells were cotransfected with pMCK1-1 and pCDNA-PMX1 or pCDNA-NUP98-PMX1 expression plasmids as described in the text. Data in (B) and (C) are expressed as the fold difference in luciferase activity obtained with test constructs compared with that obtained with the GAL4 DNA binding domain alone (B) or the empty pCDNA3.1 vector (C) (right panels). The assays were repeated three times and error bars are indicated.