FIG 6.
Brg1 is required for MEF2-mediated gene activation. (A) Analyses of Brg1-regulated activity-dependent gene expression using RNA-seq data sets obtained from BAF53b-Cre Brg1F/F Brg1 mutant and control cultured cortical neurons at 7 DIV were treated with or without KCl for 6 h. The Venn diagrams show the intersections of Brg1-activated genes and activity-induced genes (left panel) and the significant overlap between Brg1-regulated and MEF2-regulated activity-induced genes (right panel). (B) Impaired expression of activity-induced MEF2 target genes in Brg1 mutant neuronal cultures as indicated by RT-qPCR analyses. Junb was used as a non-MEF2 target gene control. (C) Western blot showing MEF2 proteins in control and Brg1 mutant neuron cultures in the absence and presence of KCl treatment for 1 h. (D) Brg1 is required for MEF2C-mediated reporter gene activation. MRE-Luc and plasmids expressing MEF2C, MEF2-VP16, or a vector control were cotransfected into cultured cortical neurons at 5 DIV. Luciferase assays were performed 24 h later. KCl was added to a group of cells 6 h before harvesting. (E) MEF2-VP16 or a vector control was transfected into cultured control or Brg1 mutant cortical neurons at 5 DIV. KCl was added at 7 DIV for 6 h. MEF2-VP16 rescued impaired MEF2 target gene Kcna1 expression in Brg1 mutant cultures in response to KCl depolarization as indicated by RT-qPCR measurement. Values in the graphs are shown as averages plus standard errors. Significance was determined using a t test or analysis of variance with a post hoc t test. ** P < 0.01 (n = 3).