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Nat Immunol. 2012 Jan 22;13(3):300-7. doi: 10.1038/ni.2210.

A self-reinforcing regulatory network triggered by limiting IL-7 activates pre-BCR signaling and differentiation.

Author information

1
Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, USA.

Abstract

The molecular crosstalk between the interleukin 7 receptor (IL-7R) and the precursor to the B cell antigen receptor (pre-BCR) in B lymphopoiesis has not been elucidated. Here we demonstrate that in pre-B cells, the IL-7R but not the pre-BCR was coupled to phosphatidylinositol-3-OH kinase (PI(3)K) and the kinase Akt; signaling by this pathway inhibited expression of recombination-activating gene 1 (Rag1) and Rag2. Attenuation of IL-7 signaling resulted in upregulation of the transcription factors Foxo1 and Pax5, which coactivated many pre-B cell genes, including Rag1, Rag2 and Blnk. Induction of Blnk (which encodes the signaling adaptor BLNK) enabled pre-BCR signaling via the signaling molecule Syk and promoted immunoglobulin light-chain rearrangement. BLNK expression also antagonized Akt activation, thereby augmenting the accumulation of Foxo1 and Pax5. This self-reinforcing molecular circuit seemed to sense limiting concentrations of IL-7 and functioned to constrain the proliferation of pre-B cells and trigger their differentiation.

PMID:
22267219
PMCID:
PMC4028049
DOI:
10.1038/ni.2210
[Indexed for MEDLINE]
Free PMC Article

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