Fig. 8.

Binding of Brm and Brg1 to the Ric-8B gene promoter decreases in the absence of C/EBPβ. (A) ROS 17/2.8 osteoblastic cells were transfected with a specific siRNA against C/EBPβ (siC/EBPβ-2). At 48 h later, cells were cross-linked with 1% formaldehyde, and the fragmented chromatin was immunoprecipitated using specific antibodies against C/EBPβ, Brm, and Brg1. The enrichment of Ric-8B promoter sequences in the precipitated chromatin fragments was quantified by QPCR using specific primers to amplify the sequence −636 to −426. Bars represent the means ± standard errors of the means of three independent experiments. Statistically significant differences were determined by the analysis of variance test. *, P < 0.05; **, P < 0.01. (B) Nuclear extracts from ROS17/2.8 cells treated as described for panel A were analyzed by Western blotting to determine C/EBPβ protein levels. Control, cells transfected with vehicle; siNR, cells transfected with an unrelated siRNA mix (for siRNA information, see Materials and Methods).