BRG1 is indispensable for IFN-γ-induced TRIM22 expression, which is dependent on the recruitment of IRF-1

The modification of chromatin structure is increasingly recognized to be an important facet of transcriptional regulation. Here, we report that Brahma-related gene 1 (BRG1), a chromatin remodeling enzyme, plays a crucial role in IFN-gamma-induced TRIM22 expression. Our results showed that IFN-gamma failed to induce TRIM22 expression in BRG1-deficient SW-13 cells, and reconstitution of BRG1 in this cell line could restore IFN-gamma induction of TRIM22. Furthermore, it was revealed that BRG1 absence, per se, did not impair IFN-gamma-induced IRF-1 expression, but blocked its access to TRIM22 promoter, and BRG1-dependent induction of TRIM22 perfectly correlated with BRG1-dependent recruitment of IRF-1 to TRIM22 promoter. We also found that the DNA-dependent ATPase domain of BRG1 was required for TRIM22 expression and IRF-1 recruitment in response to IFN-gamma stimulation, suggesting that BRG1-mediated chromatin remodeling is critical for the IFN-gamma-inducibility of TRIM22 gene. (C) 2011 Elsevier Inc. All rights reserved.