FIG. 7.

The TCF-1 B box functions as an NLS. Mammalian expression plasmids encoding GFP fused to the TCF-1 HMG DNA binding domain (GFP-TCF wt; aa 152 to 239 of TCF-1A), the DNA binding domain missing the B box (aa 152 to 228), the B box alone (aa 229 to 239), and GFP alone were transiently transfected into Cos-1 cells; 48 h later, subcellular localization was assessed by immunofluorescence of formaldehyde-fixed cells, using a Zeiss Axioskop and an Oncor CCD camera with an FITC filter. Two examples of field views are shown for each transfected construct. Single amino acid changes in the TCF-1 (GFP-STCFA and GFP-STCFD) and LEF-1 B boxes (GFP-KLEFS and GFP-KLEFR) were also assessed for their effect on nuclear localization. Single amino acid substitutions are underlined.