1. EBF1 drives hallmark B cell gene expression by enabling the interaction of PAX5 with the MLL H3K4 methyltransferase complex
- Author
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Andrew P. Joy, Rodney J. Ouellette, David Barnett, Charles E. Bullerwell, Philippe Pierre Robichaud, Pierre M. L. Deprez, Gabriel Wajnberg, Darwin D’Souza, Simi Chacko, Stephen M. Lewis, Stéphanie Fournier, and Nicolas Crapoulet
- Subjects
0301 basic medicine ,Lymphoma, B-Cell ,Molecular biology ,Science ,Antigens, CD19 ,Gene Expression ,Diseases ,Lymphocyte Activation ,Article ,CD19 ,03 medical and health sciences ,0302 clinical medicine ,immune system diseases ,Transcription (biology) ,Cell Line, Tumor ,hemic and lymphatic diseases ,Gene expression ,Transcriptional regulation ,medicine ,Humans ,Gene silencing ,Cell Lineage ,B cell ,Cancer ,B-Lymphocytes ,Multidisciplinary ,biology ,Methyltransferase complex ,Chemistry ,PAX5 Transcription Factor ,Cell Differentiation ,Methyltransferases ,Cell biology ,030104 developmental biology ,Histone ,medicine.anatomical_structure ,Oncology ,Gene Expression Regulation ,030220 oncology & carcinogenesis ,Trans-Activators ,biology.protein ,Medicine - Abstract
PAX5 and EBF1 work synergistically to regulate genes that are involved in B lymphocyte differentiation. We used the KIS-1 diffuse large B cell lymphoma cell line, which is reported to have elevated levels of PAX5 expression, to investigate the mechanism of EBF1- and PAX5-regulated gene expression. We demonstrate the lack of expression of hallmark B cell genes, including CD19, CD79b, and EBF1, in the KIS-1 cell line. Upon restoration of EBF1 expression we observed activation of CD19, CD79b and other genes with critical roles in B cell differentiation. Mass spectrometry analyses of proteins co-immunoprecipitated with PAX5 in KIS-1 identified components of the MLL H3K4 methylation complex, which drives histone modifications associated with transcription activation. Immunoblotting showed a stronger association of this complex with PAX5 in the presence of EBF1. Silencing of KMT2A, the catalytic component of MLL, repressed the ability of exogenous EBF1 to activate transcription of both CD19 and CD79b in KIS-1 cells. We also find association of PAX5 with the MLL complex and decreased CD19 expression following silencing of KMT2A in other human B cell lines. These data support an important role for the MLL complex in PAX5-mediated transcription regulation.
- Published
- 2021