Tnpo3 enables EBF1 function in conditions of antagonistic Notch signaling

Genes Dev. 2022 Aug 1;36(15-16):901-915. doi: 10.1101/gad.349696.122. Epub 2022 Sep 27.

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.

Keywords: B cell programming; B lymphopoiesis; EBF1; Notch1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Lineage / genetics
  • Chromatin
  • Glutamic Acid*
  • Immunoglobulins / genetics
  • Immunoglobulins / metabolism
  • Karyopherins / genetics
  • Mice
  • Receptors, Notch / metabolism
  • Trans-Activators* / metabolism
  • Transcription Factors / metabolism
  • beta Karyopherins / metabolism*

Substances

  • Chromatin
  • Ebf1 protein, mouse
  • Immunoglobulins
  • Karyopherins
  • Receptors, Notch
  • Trans-Activators
  • Transcription Factors
  • beta Karyopherins
  • Glutamic Acid