SPDEF regulates goblet cell hyperplasia in the airway epithelium
J. Clin. Invest. Kwon-Sik Park, et al. 117:978 doi:10.1172/JCI29176 [Go to this article.]

Figure 4
SPDEF interacts with TTF-1 via the C-terminal domain of TTF-1. (A) Mammalian 2-hybrid assay was performed using the luciferase reporter pG5-luc and pACT and pBIND as described in Methods. Full-length TTF-1 and a series of TTF-1 deletion mutants (see Supplemental Table 1) were inserted to pBIND vector. Recombinant plasmids were cotransfected with the pG5-luc plasmids, and their activity was compared with that of cells transfected with pACT-SPDEF plus pBIND–TTF-1. Values are mean ± SD (n = 3). Assays were repeated 3 times with similar results. HD, homeodomain. (B) GST pulldown assays were performed with GST-SPDEF that was immobilized on glutathione-sepharose beads. Protein extracts were prepared from HeLa cells transiently transfected with the expression plasmids encoding for 3XFLAG–TTF-1, 3XFLAGΔ14, and 3XFLAGΔ3 as described in Methods. The extracts were incubated with GST or GST-SPDEF. Both GST and GST-SPDEF beads were washed several times before boiling, run on 10% SDS-polyacrylamide gels, and analyzed by immunoblot using a monoclonal antibody that recognizes the FLAG sequences.