BRD3 function revealed in BRD2-deficient cells. (A) shRNA-mediated Brd3 knockdown in BRD2 replete vs deficient cells. Error bars represent SEM; n = 3. P-value comparisons are the results of 2-sample t tests. (B-C) BRD2 replete and deficient G1E cells in the presence and absence of GATA1 with or without retroviral BRD2 or BRD3 expression. (B) Photograph of cell pellets in wells of a 96-well plate. One representative experiment is shown of 3 with similar results. (C) mRNA levels. Error bars represent SEM; n = 3. *P < .05 that sample expressing exogenous Brd2 or Brd3 has higher mRNA levels than control Brd2-deficient cells.