| First Author | Kaeser MD | Year | 2008 |
| Journal | J Biol Chem | Volume | 283 |
| Issue | 47 | Pages | 32254-63 |
| PubMed ID | 18809673 | Mgi Jnum | J:320112 |
| Mgi Id | MGI:6869951 | Doi | 10.1074/jbc.M806061200 |
| Citation | Kaeser MD, et al. (2008) BRD7, a novel PBAF-specific SWI/SNF subunit, is required for target gene activation and repression in embryonic stem cells. J Biol Chem 283(47):32254-63 |
| abstractText | The composition of chromatin-remodeling complexes dictates how these enzymes control transcriptional programs and cellular identity. In the present study we investigated the composition of SWI/SNF complexes in embryonic stem cells (ESCs). In contrast to differentiated cells, ESCs have a biased incorporation of certain paralogous SWI/SNF subunits with low levels of BRM, BAF170, and ARID1B. Upon differentiation, the expression of these subunits increases, resulting in a higher diversity of compositionally distinct SWI/SNF enzymes. We also identified BRD7 as a novel component of the Polybromo-associated BRG1-associated factor (PBAF) complex in both ESCs and differentiated cells. Using short hairpin RNA-mediated depletion of BRG1, we showed that SWI/SNF can function as both a repressor and an activator in pluripotent cells, regulating expression of developmental modifiers and signaling components such as Nodal, ADAMTS1, BMI-1, CRABP1, and thyroid releasing hormone. Knockdown studies of PBAF-specific BRD7 and of a signature subunit within the BAF complex, ARID1A, showed that these two subcomplexes affect SWI/SNF target genes differentially, in some cases even antagonistically. This may be due to their different biochemical properties. Finally we examined the role of SWI/SNF in regulating its target genes during differentiation. We found that SWI/SNF affects recruitment of components of the preinitiation complex in a promoter-specific manner to modulate transcription positively or negatively. Taken together, our results provide insight into the function of compositionally diverse SWI/SNF enzymes that underlie their inherent gene-specific mode of action. |
