Beschreibung:
<jats:p>The induction of immunoglobulin κ light chain expression in 70Z/3 pre-B cells treated with bacterial lipopolysaccharide (LPS) requires the activation of the B cell-specific factor NF-κB, which binds to the κ enhancer motif, GGGACTTTCC. This sequence alone can function as a tissue-specific enhancer for LPS-induced gene expression. A potent inhibitor of B lymphopoiesis [transforming growth factor-β (TGF-β)] was used to explore the mechanisms in the activation of κ transcription by LPS and by interferon-γ (IFN-γ). TGF-β inhibited LPS-induced κ transcription but not the activation and in vitro binding of NF-κB. This indicates that NF-κB activation, while necessary, is not sufficient for LPS-induced κ transcription. TGF-β had no effect on IFN-γ-induced κ transcription, and NF-κB was not activated by IFN-γ. These results reveal that LPS and IFN-γ activate transcription through different mechanisms.</jats:p>