The transcription factor Duxbl mediates elimination of pre-T cells that fail β-selection

Area of Science:

• Immunology
• Molecular Biology
• Developmental Biology

Background:

• T cell development requires successful antigen-receptor gene rearrangement.
• The β-selection checkpoint ensures functional T cell receptor (TCR) β-chain rearrangement.
• The fate of T cells failing β-selection remains poorly understood.

Purpose of the Study:

• To investigate the molecular mechanisms governing the fate of T cells that fail β-selection.
• To identify molecular markers and regulators of T cell development at the β-selection checkpoint.

Main Methods:

• Single-cell transcriptome clustering and expression profiling.
• Conditional transgenic mouse models for Duxbl manipulation.
• RNA interference (RNAi) for Duxbl silencing.
• Analysis of apoptosis pathways (Oas/RNaseL, Bcl2).

Main Results:

• Low CD27 expression identifies pre-T cells with failed β-chain rearrangement.
• Transcription factor Duxbl is specifically expressed before β-selection during high recombination activity.
• Duxbl overexpression causes developmental arrest and apoptosis at the DN3-to-DN4 transition.
• Duxbl upregulates the Oas/RNaseL apoptosis pathway; Duxbl silencing reduces apoptosis.
• RNaseL deficiency or Bcl2 overexpression partially rescues Duxbl-induced developmental defects.

Conclusions:

• Duxbl acts as a critical regulator of β-selection.
• Duxbl induces apoptosis in T cells with nonfunctional β-chain rearrangements, ensuring developmental progression.
• The Oas/RNaseL pathway is a key mediator of Duxbl-induced apoptosis during T cell selection.