FIG. 6.

The region between the second and the third AT hook is required for HMGI(Y)-C/EBPβ interaction. (A) Schematic diagram of plasmids expressing HA-tagged wild-type HMGI(Y), showing the 1- 63, 1-53, and 1-43 deletion mutant proteins. The HA epitope tag, AT hooks (+), and C-terminal (----) domains are also indicated. (B) 293 cells were transiently cotransfected with C/EBPβ and the indicated HMGI(Y) mutant plasmids. Equal amounts of cell lysates (2 mg) were immunoprecipitated with anti-C/EBPβ antibodies, and the immunocomplexes were probed with either anti-C/EBPβ (upper panel) or anti-HA antibodies (lower panel). Aliquots of the same lysates (50 μg) were probed with anti-HA antibodies to evaluate the comparable expression of the transfected plasmids.