@article{StaussBrunnerBerberichSiebeltetal.2016, author = {Stauss, Dennis and Brunner, Cornelia and Berberich-Siebelt, Friederike and H{\"o}pken, Uta E. and Lipp, Martin and M{\"u}ller, Gerd}, title = {The transcriptional coactivator Bob1 promotes the development of follicular T helper cells via Bcl6}, series = {Embo Journal}, volume = {35}, journal = {Embo Journal}, number = {8}, doi = {10.15252/embj.201591459}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-189506}, pages = {881-898}, year = {2016}, abstract = {Follicular T helper (Tfh) cells are key regulators of the germinal center reaction and long-term humoral immunity. Tfh cell differentiation requires the sustained expression of the transcriptional repressor Bcl6; however, its regulation in CD4\(^+\) T cells is incompletely understood. Here, we report that the transcriptional coactivator Bob1, encoded by the Pou2af1 gene, promotes Bcl6 expression and Tfh cell development. We found that Bob1 together with the octamer transcription factors Oct1/Oct2 can directly bind to and transactivate the Bcl6 and Btla promoters. Mixed bone marrow chimeras revealed that Bob1 is required for the expression of normal levels of Bcl6 and BTLA, thereby controlling the pool size and composition of the Tfh compartment in a T cell-intrinsic manner. Our data indicate that T cell-expressed Bob1 is directly involved in Tfh cell differentiation and required for mounting normal T cell-dependent B-cell responses.}, language = {en} } @article{MuellerQuandtMarienfeldetal.2013, author = {Mueller, Kerstin and Quandt, Jasmin and Marienfeld, Ralf B. and Weihrich, Petra and Fiedler, Katja and Claussnitzer, Melina and Laumen, Helmut and Vaeth, Martin and Berberich-Siebelt, Frederike and Serfling, Edgar and Wirth, Thomas and Brunner, Cornelia}, title = {Octamer-dependent transcription in T cells is mediated by NFAT and \(NF-\kappa B\)}, series = {Nucleic Acids Research}, volume = {41}, journal = {Nucleic Acids Research}, number = {4}, issn = {1362-4962}, doi = {10.1093/nar/gks1349}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123280}, pages = {2138-2154}, year = {2013}, abstract = {The transcriptional co-activator BOB.1/OBF.1 was originally identified in B cells and is constitutively expressed throughout B cell development. BOB.1/OBF.1 associates with the transcription factors Oct1 and Oct2, thereby enhancing octamer-dependent transcription. In contrast, in T cells, BOB.1/OBF.1 expression is inducible by treatment of cells with PMA/Ionomycin or by antigen receptor engagement, indicating a marked difference in the regulation of BOB.1/OBF.1 expression in B versus T cells. The molecular mechanisms underlying the differential expression of BOB.1/OBF.1 in T and B cells remain largely unknown. Therefore, the present study focuses on mechanisms controlling the transcriptional regulation of BOB.1/OBF.1 and Oct2 in T cells. We show that both calcineurin- and \(NF-\kappa B\)-inhibitors efficiently attenuate the expression of BOB.1/OBF.1 and Oct2 in T cells. In silico analyses of the BOB.1/OBF.1 promoter revealed the presence of previously unappreciated combined NFAT/\(NF-\kappa B\) sites. An array of genetic and biochemical analyses illustrates the involvement of the \(Ca^{2+}\)/calmodulin-dependent phosphatase calcineurin as well as NFAT and \(NF-\kappa B\) transcription factors in the transcriptional regulation of octamer-dependent transcription in T cells. Conclusively, impaired expression of BOB.1/OBF.1 and Oct2 and therefore a hampered octamer-dependent transcription may participate in T cell-mediated immunodeficiency caused by the deletion of NFAT or \(NF-\kappa B\) transcription factors.}, language = {en} }