FIG. 4.

Mutation of serine 21 does not influence binding to DNA. Expression vectors encoding wild-type (WT) or S21A or S21D mutant C/EBPα were transiently transfected into COS-7 cells, and nuclear lysates were prepared. (A) Immunoblot analysis of wild-type C/EBPα and serine 21 mutant forms. (B) Gel shift analysis with nuclear lysates and a labeled oligonucleotide corresponding to the C/EBPα binding site from the human G-CSF receptor promoter. Supershifting was performed with antibody (ab) to C/EBPα.