BCL6 regulates PTPROt expression in normal naive B cells, GC centroblasts, and certain DLBCLs. (A) Normal B cells. Normal naive B cells (left) were transfected with a eGFP-BCL6 construct or empty vector and GC centroblasts (right) were transduced with a BCL6-shRNA lentiviral vector or scrambled control. (B) DLBCLs. A DLBCL cell line (DHL4) was transduced with BCL6 siRNA. In both the normal B cells (A) and the DLBCL cell line (B), BCL6 protein levels were assessed by Western blot (top panel), and PTPROt expression was evaluated by RT PCR (bottom panel). In DLBCLs, expression levels of total SYK, the upstream BCR pathway component, CD79a, and the downstream adapter protein, BLNK, were also evaluated. Error bars represent SDs from the mean for 3 independent RT-PCR assays for each condition and cell type in a representative experiment.