Expression of SRG3, a core component of mouse SWI/SNF chromatin-remodeling complex, is regulated by cooperative interactions between Sp1/Sp3 and Ets transcription factors

SRG3, a mouse homolog of yeast SW13 and human BAF155, is known to be a core component of SWI/SNF chromatin-remodeling complex. We have previously shown that SRG3 plays essential roles in early mouse embryogenesis, brain development, and T-cell development. SRG3 gene expression was differentially regulated depending on the developmental stages and exhibited tissue-specific pattern. In this study, we showed that the functional interactions between Sp and Ets family transcription factors are crucial for the SRG3 expression. Sp I and Sp3 specifically bound to the two canonical Sp-binding sites (GC boxes) at -152 and -114, and a non-canonical Sp-binding site (CCTCCT inotif) at -108 in the SRG3 promoter. Using Drosophila SL2 cells, we found that Various Sp or Ets family members activate the SRG3 promoter through these Sp- or Ets-binding sites, respectively, in a dose-dependent manner. Intriguingly, different combinatorial expression of Ets and Sp factors in SL2 cells resulted in either strong synergistic activation or repression of the SRG3 promoter activity. Moreover, the Sp-mediated activation of SRG3 promoter required the intact Ets-binding element. Taken together, these results Suggest that diverse interactions between Sp1/Sp3 and Ets factors are crucial for the SRG3 gene expression. (c) 2005 Elsevier Inc. All rights reserved.