The AT-rich DNA-binding Protein SATB2 Promotes Expression and Physical Association of Human Gγ- and Aγ-Globin Genes

Matrix attachment region (MAR)-binding protein (MARBP) has profound influence on gene transcriptional control by tethering genes to the nuclear scaffold. MARBP SATB2 is recently known as a versatile regulator functioning in the differentiation of multiple cell types including embryonic stem cells, osteoblasts and immunocytes. Roles of SATB2 in erythroid cells and its working mechanism in orchestrating target gene expression are largely unexplored. We show here that SATB2 is expressed in erythroid cells and activates gamma-globin genes by binding to MARs in their promoters and recruiting histone acetylase PCAF. Further analysis in higher-order chromatin structure shows that SATB2 affects physical proximity of human (G)gamma- and (A)gamma-globin promoters via self-association. We also found that SATB2 interacts with SATB1, which specifically activates epsilon-globin gene expression. Our results establish SATB2 as a novel gamma-globin gene regulator and provide a glimpse of the differential and cooperative roles of SATB family proteins in modulating clustered genes transcription and mediating higher-order chromatin structures.