Tnpo3 enables EBF1 function in conditions of antagonistic Notch signaling
- Marc Bayer1,
- Sören Boller1,
- Senthilkumar Ramamoothy1,
- Nikolay Zolotarev1,
- Pierre Cauchy1,
- Norimasa Iwanami2,
- Gerhard Mittler1,
- Thomas Boehm2,3 and
- Rudolf Grosschedl1
- 1Laboratory of Cellular and Molecular Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany;
- 2Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany;
- 3Faculty of Medicine, University of Freiburg, 79108 Freiburg, Germany
- Corresponding author: grosschedl{at}ie-freiburg.mpg.de
Abstract
Transcription factor EBF1 (early B cell factor 1) acts as a key regulator of B cell specification. The transcriptional network in which EBF1 operates has been extensively studied; however, the regulation of EBF1 function remains poorly defined. By mass spectrometric analysis of proteins associated with endogenous EBF1 in pro-B cells, we identified the nuclear import receptor Transportin-3 (Tnpo3) and found that it interacts with the immunoglobulin-like fold domain of EBF1. We delineated glutamic acid 271 of EBF1 as a critical residue for the association with Tnpo3. EBF1E271A showed normal nuclear localization; however, it had an impaired B cell programming ability in conditions of Notch signaling, as determined by retroviral transduction of Ebf1−/− progenitors. By RNA-seq analysis of EBF1E271A-expressing progenitors, we found an up-regulation of T lineage determinants and down-regulation of early B genes, although similar chromatin binding of EBF1E271A and EBF1wt was detected in pro-B cells expressing activated Notch1. B lineage-specific inactivation of Tnpo3 in mice resulted in a block of early B cell differentiation, accompanied by a down-regulation of B lineage genes and up-regulation of T and NK lineage genes. Taken together, our observations suggest that Tnpo3 ensures B cell programming by EBF1 in nonpermissive conditions.
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Footnotes
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Supplemental material is available for this article.
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Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.349696.122.
- Received April 25, 2022.
- Accepted September 2, 2022.
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