FIG. 9.

A model of erythroid cell-specific α-globin gene expression exerted by CP2 isoforms and their interacting protein, PIAS1. (A) Schematic diagrams illustrating functional domains (for transcriptional activation, DNA binding, and dimerization) in each CP2 isoform. (B) A proposed model depicting the involvement of CP2b/CP2c/PIAS1 in erythroid specific α-globin gene expression. Insufficient levels of proteins or protein modification may prevent full activity of the α-globin promoter in uninduced MEL cells.