Transcription factor NF-kappa B regulates inducible Oct-2 gene expression in precursor B lymphocytes

The POU transcription factors Oct-1 and Oct-2 regulate the activity of octamer-dependent promoters, including those that direct transcription from rearranged immunoglobulin genes, Unlike Oct-1, which is constitutively expressed in many cell types, Oct-2 expression is restricted primarily to B lymphocytes and can be induced in precursor B cells by stimulation with bacterial Lipopolysaccharide (LPS), However, the precise factors that mediate this induction mechanism remain unknown. In the present study, we monitored Oct-2; expression in cells arrested for the activation of NF-kappa B, an LPS-responsive member of the Rel transcription factor family. Despite stimulation with LPS, disruption of the NF-kappa B signaling pathway in precursor B cells led to the loss of inducible Oct-2 DNA binding activity in vitro and the suppression of Oct-2-directed transcription in vivo. This biochemical defect correlated with a specific block to Oct-2 gene expression at the level of transcription, whereas the expression of Oct-1 was unaffected. The finding that Oct-2 is under NF-kappa B control highlights an important cross-talk mechanism involving two distinct transcription factor families that regulate B lymphocyte function.