@article{KleinHesslingRudolfMuhammadetal.2016, author = {Klein-Hessling, Stefan and Rudolf, Ronald and Muhammad, Khalid and Knobeloch, Klaus-Peter and Maqbool, Muhammad Ahmad and Cauchy, Pierre and Andrau, Jean-Christophe and Avots, Andris and Talora, Claudio and Ellenrieder, Volker and Screpanti, Isabella and Serfling, Edgar and Patra, Amiya Kumar}, title = {A threshold level of NFATc1 activity facilitates thymocyte differentiation and opposes notch-driven leukaemia development}, series = {Nature Communications}, volume = {7}, journal = {Nature Communications}, doi = {10.1038/ncomms11841}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172974}, year = {2016}, abstract = {NFATc1 plays a critical role in double-negative thymocyte survival and differentiation. However, the signals that regulate Nfatc1 expression are incompletely characterized. Here we show a developmental stage-specific differential expression pattern of Nfatc1 driven by the distal (P1) or proximal (P2) promoters in thymocytes. Whereas, preTCR-negative thymocytes exhibit only P2 promoter-derived Nfatc1β expression, preTCR-positive thymocytes express both Nfatc1β and P1 promoter-derived Nfatc1α transcripts. Inducing NFATc1α activity from P1 promoter in preTCR-negative thymocytes, in addition to the NFATc1β from P2 promoter impairs thymocyte development resulting in severe T-cell lymphopenia. In addition, we show that NFATc1 activity suppresses the B-lineage potential of immature thymocytes, and consolidates their differentiation to T cells. Further, in the pTCR-positive DN3 cells, a threshold level of NFATc1 activity is vital in facilitating T-cell differentiation and to prevent Notch3-induced T-acute lymphoblastic leukaemia. Altogether, our results show NFATc1 activity is crucial in determining the T-cell fate of thymocytes.}, language = {en} } @article{TeloracPrykhozhijSchoeneetal.2016, author = {Telorac, Jonas and Prykhozhij, Sergey V. and Sch{\"o}ne, Stefanie and Meierhofer, David and Sauer, Sascha and Thomas-Chollier, Morgane and Meijsing, Sebastiaan H.}, title = {Identification and characterization of DNA sequences that prevent glucocorticoid receptor binding to nearby response elements}, series = {Nucleic Acids Research}, volume = {44}, journal = {Nucleic Acids Research}, number = {13}, doi = {10.1093/nar/gkw203}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166330}, pages = {6142-6156}, year = {2016}, abstract = {Out of the myriad of potential DNA binding sites of the glucocorticoid receptor (GR) found in the human genome, only a cell-type specific minority is actually bound, indicating that the presence of a recognition sequence alone is insufficient to specify where GR binds. Cooperative interactions with other transcription factors (TFs) are known to contribute to binding specificity. Here, we reasoned that sequence signals preventing GR recruitment to certain loci provide an alternative means to confer specificity. Motif analyses uncovered candidate Negative Regulatory Sequences (NRSs) that interfere with genomic GR binding. Subsequent functional analyses demonstrated that NRSs indeed prevent GR binding to nearby response elements. We show that NRS activity is conserved across species, found in most tissues and that they also interfere with the genomic binding of other TFs. Interestingly, the effects of NRSs appear not to be a simple consequence of changes in chromatin accessibility. Instead, we find that NRSs interact with proteins found at sub-nuclear structures called paraspeckles and that these proteins might mediate the repressive effects of NRSs. Together, our studies suggest that the joint influence of positive and negative sequence signals partition the genome into regions where GR can bind and those where it cannot.}, language = {en} }