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.
This work was funded by National Institutes of Health Grants DK50107 and DK67633 (to E. H. B.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
