Activation of Mouse Tcrb: Uncoupling RUNX1 Function from Its Cooperative Binding with ETS1
| Autor: | Eugene M. Oltz, Oleg Osipovich, Jiang-yang Zhao, Olivia I. Koues, Kinjal Majumder |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Genetics T cell Immunology T-cell receptor Promoter Biology Chromatin 03 medical and health sciences 030104 developmental biology 0302 clinical medicine medicine.anatomical_structure Transcription (biology) 030220 oncology & carcinogenesis medicine Immunology and Allergy Nucleosome Enhancer Transcription factor |
| Zdroj: | The Journal of Immunology. 199:1131-1141 |
| ISSN: | 1550-6606 0022-1767 |
| DOI: | 10.4049/jimmunol.1700146 |
| Popis: | T lineage commitment requires the coordination of key transcription factors (TFs) in multipotent progenitors that transition them away from other lineages and cement T cell identity. Two important TFs for the multipotent progenitors to T lineage transition are RUNX1 and ETS1, which bind cooperatively to composite sites throughout the genome, especially in regulatory elements for genes involved in T lymphopoiesis. Activation of the TCR β (Tcrb) locus in committed thymocytes is a critical process for continued development of these cells, and is mediated by an enhancer, Eβ, which harbors two RUNX-ETS composite sites. An outstanding issue in understanding T cell gene expression programs is whether RUNX1 and ETS1 have independent functions in enhancer activation that can be dissected from cooperative binding. We now show that RUNX1 is sufficient to activate the endogenous mouse Eβ element and its neighboring 25 kb region by independently tethering this TF without coincidental ETS1 binding. Moreover, RUNX1 is sufficient for long-range promoter-Eβ looping, nucleosome clearance, and robust transcription throughout the Tcrb recombination center, spanning both DβJβ clusters. We also find that a RUNX1 domain, termed the negative regulatory domain for DNA binding, can compensate for the loss of ETS1 binding at adjacent sites. Thus, we have defined independent roles for RUNX1 in the activation of a T cell developmental enhancer, as well as its ability to mediate specific changes in chromatin landscapes that accompany long-range induction of recombination center promoters. |
| Databáze: | OpenAIRE |
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