Dynamic GATA factor interplay at a multicomponent regulatory region of the GATA-2 locus

Given the simplicity of the DNA sequence that mediates binding of GATA transcription factors, GATA motifs reside throughout chromosomal DNA. However, chromatin immunoprecipitation analysis has revealed that GATA-1 discriminates exquisitely among these sites. GATA-2 selectively occupies the -2.8-kilobase (kb) region of the GATA-2 locus in the active state despite there being numerous GATA motifs throughout the locus. The GATA-1-mediated displacement of GATA-2 is tightly coupled to repression of GATA-2 transcription. We have used high resolution chromatin immunoprecipitation to show that GATA-1 and GATA-2 occupy two additional regions, -3.9 and -1.8 kb of the GATA-2 locus. GATA-1 and GATA-2 had distinct preferences for occupancy at these regions, with GATA-1 and GATA-2 occupancy highest at the -3.9- and -1.8-kb regions, respectively. Activation of an estrogen receptor fusion to GATA-1 (ER-GATA-1) induced similar kinetics of ER-GATA-1 occupancy and GATA-2 displacement at the sites. In the transcriptionally active state, DNase I hypersensitive sites (HSs) were detected at the -3.9- and -1.8-kb regions, with a weak HS at the -2.8-kb region. Whereas ER-GATA-1-instigated repression abolished the -1.8-kb HS, the -3.9-kb HS persisted in the repressed state. Transient transfection analysis provided evidence that the -3.9-kb region functions distinctly from the -2.8- and -1.8-kb regions. We propose that GATA-2 transcription is regulated via the collective actions of complexes assembled at the -2.8- and -1.8-kb regions, which share similar properties, and through a qualitatively distinct activity of the -3.9-kb complex.